Version:  2.0.40 2.2.26 2.4.37 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0

Linux/drivers/acpi/video.c

  1 /*
  2  *  video.c - ACPI Video Driver
  3  *
  4  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
  5  *  Copyright (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
  6  *  Copyright (C) 2006 Thomas Tuttle <linux-kernel@ttuttle.net>
  7  *
  8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  9  *
 10  *  This program is free software; you can redistribute it and/or modify
 11  *  it under the terms of the GNU General Public License as published by
 12  *  the Free Software Foundation; either version 2 of the License, or (at
 13  *  your option) any later version.
 14  *
 15  *  This program is distributed in the hope that it will be useful, but
 16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
 17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 18  *  General Public License for more details.
 19  *
 20  *  You should have received a copy of the GNU General Public License along
 21  *  with this program; if not, write to the Free Software Foundation, Inc.,
 22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 23  *
 24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 25  */
 26 
 27 #include <linux/kernel.h>
 28 #include <linux/module.h>
 29 #include <linux/init.h>
 30 #include <linux/types.h>
 31 #include <linux/list.h>
 32 #include <linux/mutex.h>
 33 #include <linux/input.h>
 34 #include <linux/backlight.h>
 35 #include <linux/thermal.h>
 36 #include <linux/sort.h>
 37 #include <linux/pci.h>
 38 #include <linux/pci_ids.h>
 39 #include <linux/slab.h>
 40 #include <linux/dmi.h>
 41 #include <linux/suspend.h>
 42 #include <linux/acpi.h>
 43 #include <acpi/video.h>
 44 #include <asm/uaccess.h>
 45 
 46 #include "internal.h"
 47 
 48 #define ACPI_VIDEO_BUS_NAME             "Video Bus"
 49 #define ACPI_VIDEO_DEVICE_NAME          "Video Device"
 50 #define ACPI_VIDEO_NOTIFY_SWITCH        0x80
 51 #define ACPI_VIDEO_NOTIFY_PROBE         0x81
 52 #define ACPI_VIDEO_NOTIFY_CYCLE         0x82
 53 #define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT   0x83
 54 #define ACPI_VIDEO_NOTIFY_PREV_OUTPUT   0x84
 55 
 56 #define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS      0x85
 57 #define ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS        0x86
 58 #define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS        0x87
 59 #define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS       0x88
 60 #define ACPI_VIDEO_NOTIFY_DISPLAY_OFF           0x89
 61 
 62 #define MAX_NAME_LEN    20
 63 
 64 #define _COMPONENT              ACPI_VIDEO_COMPONENT
 65 ACPI_MODULE_NAME("video");
 66 
 67 MODULE_AUTHOR("Bruno Ducrot");
 68 MODULE_DESCRIPTION("ACPI Video Driver");
 69 MODULE_LICENSE("GPL");
 70 
 71 static bool brightness_switch_enabled = 1;
 72 module_param(brightness_switch_enabled, bool, 0644);
 73 
 74 /*
 75  * By default, we don't allow duplicate ACPI video bus devices
 76  * under the same VGA controller
 77  */
 78 static bool allow_duplicates;
 79 module_param(allow_duplicates, bool, 0644);
 80 
 81 /*
 82  * For Windows 8 systems: used to decide if video module
 83  * should skip registering backlight interface of its own.
 84  */
 85 static int use_native_backlight_param = -1;
 86 module_param_named(use_native_backlight, use_native_backlight_param, int, 0444);
 87 static bool use_native_backlight_dmi = true;
 88 
 89 static int register_count;
 90 static struct mutex video_list_lock;
 91 static struct list_head video_bus_head;
 92 static int acpi_video_bus_add(struct acpi_device *device);
 93 static int acpi_video_bus_remove(struct acpi_device *device);
 94 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
 95 
 96 static const struct acpi_device_id video_device_ids[] = {
 97         {ACPI_VIDEO_HID, 0},
 98         {"", 0},
 99 };
100 MODULE_DEVICE_TABLE(acpi, video_device_ids);
101 
102 static struct acpi_driver acpi_video_bus = {
103         .name = "video",
104         .class = ACPI_VIDEO_CLASS,
105         .ids = video_device_ids,
106         .ops = {
107                 .add = acpi_video_bus_add,
108                 .remove = acpi_video_bus_remove,
109                 .notify = acpi_video_bus_notify,
110                 },
111 };
112 
113 struct acpi_video_bus_flags {
114         u8 multihead:1;         /* can switch video heads */
115         u8 rom:1;               /* can retrieve a video rom */
116         u8 post:1;              /* can configure the head to */
117         u8 reserved:5;
118 };
119 
120 struct acpi_video_bus_cap {
121         u8 _DOS:1;              /* Enable/Disable output switching */
122         u8 _DOD:1;              /* Enumerate all devices attached to display adapter */
123         u8 _ROM:1;              /* Get ROM Data */
124         u8 _GPD:1;              /* Get POST Device */
125         u8 _SPD:1;              /* Set POST Device */
126         u8 _VPO:1;              /* Video POST Options */
127         u8 reserved:2;
128 };
129 
130 struct acpi_video_device_attrib {
131         u32 display_index:4;    /* A zero-based instance of the Display */
132         u32 display_port_attachment:4;  /* This field differentiates the display type */
133         u32 display_type:4;     /* Describe the specific type in use */
134         u32 vendor_specific:4;  /* Chipset Vendor Specific */
135         u32 bios_can_detect:1;  /* BIOS can detect the device */
136         u32 depend_on_vga:1;    /* Non-VGA output device whose power is related to
137                                    the VGA device. */
138         u32 pipe_id:3;          /* For VGA multiple-head devices. */
139         u32 reserved:10;        /* Must be 0 */
140         u32 device_id_scheme:1; /* Device ID Scheme */
141 };
142 
143 struct acpi_video_enumerated_device {
144         union {
145                 u32 int_val;
146                 struct acpi_video_device_attrib attrib;
147         } value;
148         struct acpi_video_device *bind_info;
149 };
150 
151 struct acpi_video_bus {
152         struct acpi_device *device;
153         bool backlight_registered;
154         bool backlight_notifier_registered;
155         u8 dos_setting;
156         struct acpi_video_enumerated_device *attached_array;
157         u8 attached_count;
158         u8 child_count;
159         struct acpi_video_bus_cap cap;
160         struct acpi_video_bus_flags flags;
161         struct list_head video_device_list;
162         struct mutex device_list_lock;  /* protects video_device_list */
163         struct list_head entry;
164         struct input_dev *input;
165         char phys[32];  /* for input device */
166         struct notifier_block pm_nb;
167         struct notifier_block backlight_nb;
168 };
169 
170 struct acpi_video_device_flags {
171         u8 crt:1;
172         u8 lcd:1;
173         u8 tvout:1;
174         u8 dvi:1;
175         u8 bios:1;
176         u8 unknown:1;
177         u8 notify:1;
178         u8 reserved:1;
179 };
180 
181 struct acpi_video_device_cap {
182         u8 _ADR:1;              /* Return the unique ID */
183         u8 _BCL:1;              /* Query list of brightness control levels supported */
184         u8 _BCM:1;              /* Set the brightness level */
185         u8 _BQC:1;              /* Get current brightness level */
186         u8 _BCQ:1;              /* Some buggy BIOS uses _BCQ instead of _BQC */
187         u8 _DDC:1;              /* Return the EDID for this device */
188 };
189 
190 struct acpi_video_brightness_flags {
191         u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
192         u8 _BCL_reversed:1;             /* _BCL package is in a reversed order */
193         u8 _BQC_use_index:1;            /* _BQC returns an index value */
194 };
195 
196 struct acpi_video_device_brightness {
197         int curr;
198         int count;
199         int *levels;
200         struct acpi_video_brightness_flags flags;
201 };
202 
203 struct acpi_video_device {
204         unsigned long device_id;
205         struct acpi_video_device_flags flags;
206         struct acpi_video_device_cap cap;
207         struct list_head entry;
208         struct delayed_work switch_brightness_work;
209         int switch_brightness_event;
210         struct acpi_video_bus *video;
211         struct acpi_device *dev;
212         struct acpi_video_device_brightness *brightness;
213         struct backlight_device *backlight;
214         struct thermal_cooling_device *cooling_dev;
215 };
216 
217 static const char device_decode[][30] = {
218         "motherboard VGA device",
219         "PCI VGA device",
220         "AGP VGA device",
221         "UNKNOWN",
222 };
223 
224 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
225 static void acpi_video_device_rebind(struct acpi_video_bus *video);
226 static void acpi_video_device_bind(struct acpi_video_bus *video,
227                                    struct acpi_video_device *device);
228 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
229 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
230                         int level);
231 static int acpi_video_device_lcd_get_level_current(
232                         struct acpi_video_device *device,
233                         unsigned long long *level, bool raw);
234 static int acpi_video_get_next_level(struct acpi_video_device *device,
235                                      u32 level_current, u32 event);
236 static void acpi_video_switch_brightness(struct work_struct *work);
237 
238 static bool acpi_video_use_native_backlight(void)
239 {
240         if (use_native_backlight_param != -1)
241                 return use_native_backlight_param;
242         else
243                 return use_native_backlight_dmi;
244 }
245 
246 bool acpi_video_verify_backlight_support(void)
247 {
248         if (acpi_osi_is_win8() && acpi_video_use_native_backlight() &&
249             backlight_device_registered(BACKLIGHT_RAW))
250                 return false;
251         return acpi_video_backlight_support();
252 }
253 EXPORT_SYMBOL_GPL(acpi_video_verify_backlight_support);
254 
255 /* backlight device sysfs support */
256 static int acpi_video_get_brightness(struct backlight_device *bd)
257 {
258         unsigned long long cur_level;
259         int i;
260         struct acpi_video_device *vd = bl_get_data(bd);
261 
262         if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
263                 return -EINVAL;
264         for (i = 2; i < vd->brightness->count; i++) {
265                 if (vd->brightness->levels[i] == cur_level)
266                         /*
267                          * The first two entries are special - see page 575
268                          * of the ACPI spec 3.0
269                          */
270                         return i - 2;
271         }
272         return 0;
273 }
274 
275 static int acpi_video_set_brightness(struct backlight_device *bd)
276 {
277         int request_level = bd->props.brightness + 2;
278         struct acpi_video_device *vd = bl_get_data(bd);
279 
280         cancel_delayed_work(&vd->switch_brightness_work);
281         return acpi_video_device_lcd_set_level(vd,
282                                 vd->brightness->levels[request_level]);
283 }
284 
285 static const struct backlight_ops acpi_backlight_ops = {
286         .get_brightness = acpi_video_get_brightness,
287         .update_status  = acpi_video_set_brightness,
288 };
289 
290 /* thermal cooling device callbacks */
291 static int video_get_max_state(struct thermal_cooling_device *cooling_dev, unsigned
292                                long *state)
293 {
294         struct acpi_device *device = cooling_dev->devdata;
295         struct acpi_video_device *video = acpi_driver_data(device);
296 
297         *state = video->brightness->count - 3;
298         return 0;
299 }
300 
301 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsigned
302                                long *state)
303 {
304         struct acpi_device *device = cooling_dev->devdata;
305         struct acpi_video_device *video = acpi_driver_data(device);
306         unsigned long long level;
307         int offset;
308 
309         if (acpi_video_device_lcd_get_level_current(video, &level, false))
310                 return -EINVAL;
311         for (offset = 2; offset < video->brightness->count; offset++)
312                 if (level == video->brightness->levels[offset]) {
313                         *state = video->brightness->count - offset - 1;
314                         return 0;
315                 }
316 
317         return -EINVAL;
318 }
319 
320 static int
321 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
322 {
323         struct acpi_device *device = cooling_dev->devdata;
324         struct acpi_video_device *video = acpi_driver_data(device);
325         int level;
326 
327         if (state >= video->brightness->count - 2)
328                 return -EINVAL;
329 
330         state = video->brightness->count - state;
331         level = video->brightness->levels[state - 1];
332         return acpi_video_device_lcd_set_level(video, level);
333 }
334 
335 static const struct thermal_cooling_device_ops video_cooling_ops = {
336         .get_max_state = video_get_max_state,
337         .get_cur_state = video_get_cur_state,
338         .set_cur_state = video_set_cur_state,
339 };
340 
341 /*
342  * --------------------------------------------------------------------------
343  *                             Video Management
344  * --------------------------------------------------------------------------
345  */
346 
347 static int
348 acpi_video_device_lcd_query_levels(struct acpi_video_device *device,
349                                    union acpi_object **levels)
350 {
351         int status;
352         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
353         union acpi_object *obj;
354 
355 
356         *levels = NULL;
357 
358         status = acpi_evaluate_object(device->dev->handle, "_BCL", NULL, &buffer);
359         if (!ACPI_SUCCESS(status))
360                 return status;
361         obj = (union acpi_object *)buffer.pointer;
362         if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
363                 printk(KERN_ERR PREFIX "Invalid _BCL data\n");
364                 status = -EFAULT;
365                 goto err;
366         }
367 
368         *levels = obj;
369 
370         return 0;
371 
372 err:
373         kfree(buffer.pointer);
374 
375         return status;
376 }
377 
378 static int
379 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
380 {
381         int status;
382         int state;
383 
384         status = acpi_execute_simple_method(device->dev->handle,
385                                             "_BCM", level);
386         if (ACPI_FAILURE(status)) {
387                 ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
388                 return -EIO;
389         }
390 
391         device->brightness->curr = level;
392         for (state = 2; state < device->brightness->count; state++)
393                 if (level == device->brightness->levels[state]) {
394                         if (device->backlight)
395                                 device->backlight->props.brightness = state - 2;
396                         return 0;
397                 }
398 
399         ACPI_ERROR((AE_INFO, "Current brightness invalid"));
400         return -EINVAL;
401 }
402 
403 /*
404  * For some buggy _BQC methods, we need to add a constant value to
405  * the _BQC return value to get the actual current brightness level
406  */
407 
408 static int bqc_offset_aml_bug_workaround;
409 static int __init video_set_bqc_offset(const struct dmi_system_id *d)
410 {
411         bqc_offset_aml_bug_workaround = 9;
412         return 0;
413 }
414 
415 static int __init video_disable_native_backlight(const struct dmi_system_id *d)
416 {
417         use_native_backlight_dmi = false;
418         return 0;
419 }
420 
421 static struct dmi_system_id video_dmi_table[] __initdata = {
422         /*
423          * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
424          */
425         {
426          .callback = video_set_bqc_offset,
427          .ident = "Acer Aspire 5720",
428          .matches = {
429                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
430                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
431                 },
432         },
433         {
434          .callback = video_set_bqc_offset,
435          .ident = "Acer Aspire 5710Z",
436          .matches = {
437                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
438                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
439                 },
440         },
441         {
442          .callback = video_set_bqc_offset,
443          .ident = "eMachines E510",
444          .matches = {
445                 DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
446                 DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
447                 },
448         },
449         {
450          .callback = video_set_bqc_offset,
451          .ident = "Acer Aspire 5315",
452          .matches = {
453                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
454                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
455                 },
456         },
457         {
458          .callback = video_set_bqc_offset,
459          .ident = "Acer Aspire 7720",
460          .matches = {
461                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
462                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
463                 },
464         },
465 
466         /*
467          * These models have a working acpi_video backlight control, and using
468          * native backlight causes a regression where backlight does not work
469          * when userspace is not handling brightness key events. Disable
470          * native_backlight on these to fix this:
471          * https://bugzilla.kernel.org/show_bug.cgi?id=81691
472          */
473         {
474          .callback = video_disable_native_backlight,
475          .ident = "ThinkPad T420",
476          .matches = {
477                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
478                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T420"),
479                 },
480         },
481         {
482          .callback = video_disable_native_backlight,
483          .ident = "ThinkPad T520",
484          .matches = {
485                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
486                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T520"),
487                 },
488         },
489         {
490          .callback = video_disable_native_backlight,
491          .ident = "ThinkPad X201s",
492          .matches = {
493                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
494                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201s"),
495                 },
496         },
497 
498         /* The native backlight controls do not work on some older machines */
499         {
500          /* https://bugs.freedesktop.org/show_bug.cgi?id=81515 */
501          .callback = video_disable_native_backlight,
502          .ident = "HP ENVY 15 Notebook",
503          .matches = {
504                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
505                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ENVY 15 Notebook PC"),
506                 },
507         },
508 
509         {
510          .callback = video_disable_native_backlight,
511          .ident = "SAMSUNG 870Z5E/880Z5E/680Z5E",
512          .matches = {
513                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
514                 DMI_MATCH(DMI_PRODUCT_NAME, "870Z5E/880Z5E/680Z5E"),
515                 },
516         },
517         {
518          .callback = video_disable_native_backlight,
519          .ident = "SAMSUNG 370R4E/370R4V/370R5E/3570RE/370R5V",
520          .matches = {
521                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
522                 DMI_MATCH(DMI_PRODUCT_NAME, "370R4E/370R4V/370R5E/3570RE/370R5V"),
523                 },
524         },
525         {
526          /* https://bugzilla.redhat.com/show_bug.cgi?id=1186097 */
527          .callback = video_disable_native_backlight,
528          .ident = "SAMSUNG 3570R/370R/470R/450R/510R/4450RV",
529          .matches = {
530                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
531                 DMI_MATCH(DMI_PRODUCT_NAME, "3570R/370R/470R/450R/510R/4450RV"),
532                 },
533         },
534         {
535          /* https://bugzilla.redhat.com/show_bug.cgi?id=1094948 */
536          .callback = video_disable_native_backlight,
537          .ident = "SAMSUNG 730U3E/740U3E",
538          .matches = {
539                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
540                 DMI_MATCH(DMI_PRODUCT_NAME, "730U3E/740U3E"),
541                 },
542         },
543         {
544          /* https://bugs.freedesktop.org/show_bug.cgi?id=87286 */
545          .callback = video_disable_native_backlight,
546          .ident = "SAMSUNG 900X3C/900X3D/900X3E/900X4C/900X4D",
547          .matches = {
548                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
549                 DMI_MATCH(DMI_PRODUCT_NAME, "900X3C/900X3D/900X3E/900X4C/900X4D"),
550                 },
551         },
552 
553         {
554          /* https://bugzilla.redhat.com/show_bug.cgi?id=1163574 */
555          .callback = video_disable_native_backlight,
556          .ident = "Dell XPS15 L521X",
557          .matches = {
558                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
559                 DMI_MATCH(DMI_PRODUCT_NAME, "XPS L521X"),
560                 },
561         },
562         {}
563 };
564 
565 static unsigned long long
566 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
567                               unsigned long long bqc_value)
568 {
569         unsigned long long level;
570 
571         if (device->brightness->flags._BQC_use_index) {
572                 /*
573                  * _BQC returns an index that doesn't account for
574                  * the first 2 items with special meaning, so we need
575                  * to compensate for that by offsetting ourselves
576                  */
577                 if (device->brightness->flags._BCL_reversed)
578                         bqc_value = device->brightness->count - 3 - bqc_value;
579 
580                 level = device->brightness->levels[bqc_value + 2];
581         } else {
582                 level = bqc_value;
583         }
584 
585         level += bqc_offset_aml_bug_workaround;
586 
587         return level;
588 }
589 
590 static int
591 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
592                                         unsigned long long *level, bool raw)
593 {
594         acpi_status status = AE_OK;
595         int i;
596 
597         if (device->cap._BQC || device->cap._BCQ) {
598                 char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
599 
600                 status = acpi_evaluate_integer(device->dev->handle, buf,
601                                                 NULL, level);
602                 if (ACPI_SUCCESS(status)) {
603                         if (raw) {
604                                 /*
605                                  * Caller has indicated he wants the raw
606                                  * value returned by _BQC, so don't furtherly
607                                  * mess with the value.
608                                  */
609                                 return 0;
610                         }
611 
612                         *level = acpi_video_bqc_value_to_level(device, *level);
613 
614                         for (i = 2; i < device->brightness->count; i++)
615                                 if (device->brightness->levels[i] == *level) {
616                                         device->brightness->curr = *level;
617                                         return 0;
618                                 }
619                         /*
620                          * BQC returned an invalid level.
621                          * Stop using it.
622                          */
623                         ACPI_WARNING((AE_INFO,
624                                       "%s returned an invalid level",
625                                       buf));
626                         device->cap._BQC = device->cap._BCQ = 0;
627                 } else {
628                         /*
629                          * Fixme:
630                          * should we return an error or ignore this failure?
631                          * dev->brightness->curr is a cached value which stores
632                          * the correct current backlight level in most cases.
633                          * ACPI video backlight still works w/ buggy _BQC.
634                          * http://bugzilla.kernel.org/show_bug.cgi?id=12233
635                          */
636                         ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
637                         device->cap._BQC = device->cap._BCQ = 0;
638                 }
639         }
640 
641         *level = device->brightness->curr;
642         return 0;
643 }
644 
645 static int
646 acpi_video_device_EDID(struct acpi_video_device *device,
647                        union acpi_object **edid, ssize_t length)
648 {
649         int status;
650         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
651         union acpi_object *obj;
652         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
653         struct acpi_object_list args = { 1, &arg0 };
654 
655 
656         *edid = NULL;
657 
658         if (!device)
659                 return -ENODEV;
660         if (length == 128)
661                 arg0.integer.value = 1;
662         else if (length == 256)
663                 arg0.integer.value = 2;
664         else
665                 return -EINVAL;
666 
667         status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
668         if (ACPI_FAILURE(status))
669                 return -ENODEV;
670 
671         obj = buffer.pointer;
672 
673         if (obj && obj->type == ACPI_TYPE_BUFFER)
674                 *edid = obj;
675         else {
676                 printk(KERN_ERR PREFIX "Invalid _DDC data\n");
677                 status = -EFAULT;
678                 kfree(obj);
679         }
680 
681         return status;
682 }
683 
684 /* bus */
685 
686 /*
687  *  Arg:
688  *      video           : video bus device pointer
689  *      bios_flag       :
690  *              0.      The system BIOS should NOT automatically switch(toggle)
691  *                      the active display output.
692  *              1.      The system BIOS should automatically switch (toggle) the
693  *                      active display output. No switch event.
694  *              2.      The _DGS value should be locked.
695  *              3.      The system BIOS should not automatically switch (toggle) the
696  *                      active display output, but instead generate the display switch
697  *                      event notify code.
698  *      lcd_flag        :
699  *              0.      The system BIOS should automatically control the brightness level
700  *                      of the LCD when the power changes from AC to DC
701  *              1.      The system BIOS should NOT automatically control the brightness
702  *                      level of the LCD when the power changes from AC to DC.
703  *  Return Value:
704  *              -EINVAL wrong arg.
705  */
706 
707 static int
708 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
709 {
710         acpi_status status;
711 
712         if (!video->cap._DOS)
713                 return 0;
714 
715         if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
716                 return -EINVAL;
717         video->dos_setting = (lcd_flag << 2) | bios_flag;
718         status = acpi_execute_simple_method(video->device->handle, "_DOS",
719                                             (lcd_flag << 2) | bios_flag);
720         if (ACPI_FAILURE(status))
721                 return -EIO;
722 
723         return 0;
724 }
725 
726 /*
727  * Simple comparison function used to sort backlight levels.
728  */
729 
730 static int
731 acpi_video_cmp_level(const void *a, const void *b)
732 {
733         return *(int *)a - *(int *)b;
734 }
735 
736 /*
737  * Decides if _BQC/_BCQ for this system is usable
738  *
739  * We do this by changing the level first and then read out the current
740  * brightness level, if the value does not match, find out if it is using
741  * index. If not, clear the _BQC/_BCQ capability.
742  */
743 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
744                                 int max_level, int current_level)
745 {
746         struct acpi_video_device_brightness *br = device->brightness;
747         int result;
748         unsigned long long level;
749         int test_level;
750 
751         /* don't mess with existing known broken systems */
752         if (bqc_offset_aml_bug_workaround)
753                 return 0;
754 
755         /*
756          * Some systems always report current brightness level as maximum
757          * through _BQC, we need to test another value for them.
758          */
759         test_level = current_level == max_level ? br->levels[3] : max_level;
760 
761         result = acpi_video_device_lcd_set_level(device, test_level);
762         if (result)
763                 return result;
764 
765         result = acpi_video_device_lcd_get_level_current(device, &level, true);
766         if (result)
767                 return result;
768 
769         if (level != test_level) {
770                 /* buggy _BQC found, need to find out if it uses index */
771                 if (level < br->count) {
772                         if (br->flags._BCL_reversed)
773                                 level = br->count - 3 - level;
774                         if (br->levels[level + 2] == test_level)
775                                 br->flags._BQC_use_index = 1;
776                 }
777 
778                 if (!br->flags._BQC_use_index)
779                         device->cap._BQC = device->cap._BCQ = 0;
780         }
781 
782         return 0;
783 }
784 
785 
786 /*
787  *  Arg:
788  *      device  : video output device (LCD, CRT, ..)
789  *
790  *  Return Value:
791  *      Maximum brightness level
792  *
793  *  Allocate and initialize device->brightness.
794  */
795 
796 static int
797 acpi_video_init_brightness(struct acpi_video_device *device)
798 {
799         union acpi_object *obj = NULL;
800         int i, max_level = 0, count = 0, level_ac_battery = 0;
801         unsigned long long level, level_old;
802         union acpi_object *o;
803         struct acpi_video_device_brightness *br = NULL;
804         int result = -EINVAL;
805         u32 value;
806 
807         if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
808                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
809                                                 "LCD brightness level\n"));
810                 goto out;
811         }
812 
813         if (obj->package.count < 2)
814                 goto out;
815 
816         br = kzalloc(sizeof(*br), GFP_KERNEL);
817         if (!br) {
818                 printk(KERN_ERR "can't allocate memory\n");
819                 result = -ENOMEM;
820                 goto out;
821         }
822 
823         br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
824                                 GFP_KERNEL);
825         if (!br->levels) {
826                 result = -ENOMEM;
827                 goto out_free;
828         }
829 
830         for (i = 0; i < obj->package.count; i++) {
831                 o = (union acpi_object *)&obj->package.elements[i];
832                 if (o->type != ACPI_TYPE_INTEGER) {
833                         printk(KERN_ERR PREFIX "Invalid data\n");
834                         continue;
835                 }
836                 value = (u32) o->integer.value;
837                 /* Skip duplicate entries */
838                 if (count > 2 && br->levels[count - 1] == value)
839                         continue;
840 
841                 br->levels[count] = value;
842 
843                 if (br->levels[count] > max_level)
844                         max_level = br->levels[count];
845                 count++;
846         }
847 
848         /*
849          * some buggy BIOS don't export the levels
850          * when machine is on AC/Battery in _BCL package.
851          * In this case, the first two elements in _BCL packages
852          * are also supported brightness levels that OS should take care of.
853          */
854         for (i = 2; i < count; i++) {
855                 if (br->levels[i] == br->levels[0])
856                         level_ac_battery++;
857                 if (br->levels[i] == br->levels[1])
858                         level_ac_battery++;
859         }
860 
861         if (level_ac_battery < 2) {
862                 level_ac_battery = 2 - level_ac_battery;
863                 br->flags._BCL_no_ac_battery_levels = 1;
864                 for (i = (count - 1 + level_ac_battery); i >= 2; i--)
865                         br->levels[i] = br->levels[i - level_ac_battery];
866                 count += level_ac_battery;
867         } else if (level_ac_battery > 2)
868                 ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
869 
870         /* Check if the _BCL package is in a reversed order */
871         if (max_level == br->levels[2]) {
872                 br->flags._BCL_reversed = 1;
873                 sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
874                         acpi_video_cmp_level, NULL);
875         } else if (max_level != br->levels[count - 1])
876                 ACPI_ERROR((AE_INFO,
877                             "Found unordered _BCL package"));
878 
879         br->count = count;
880         device->brightness = br;
881 
882         /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
883         br->curr = level = max_level;
884 
885         if (!device->cap._BQC)
886                 goto set_level;
887 
888         result = acpi_video_device_lcd_get_level_current(device,
889                                                          &level_old, true);
890         if (result)
891                 goto out_free_levels;
892 
893         result = acpi_video_bqc_quirk(device, max_level, level_old);
894         if (result)
895                 goto out_free_levels;
896         /*
897          * cap._BQC may get cleared due to _BQC is found to be broken
898          * in acpi_video_bqc_quirk, so check again here.
899          */
900         if (!device->cap._BQC)
901                 goto set_level;
902 
903         level = acpi_video_bqc_value_to_level(device, level_old);
904         /*
905          * On some buggy laptops, _BQC returns an uninitialized
906          * value when invoked for the first time, i.e.
907          * level_old is invalid (no matter whether it's a level
908          * or an index). Set the backlight to max_level in this case.
909          */
910         for (i = 2; i < br->count; i++)
911                 if (level == br->levels[i])
912                         break;
913         if (i == br->count || !level)
914                 level = max_level;
915 
916 set_level:
917         result = acpi_video_device_lcd_set_level(device, level);
918         if (result)
919                 goto out_free_levels;
920 
921         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
922                           "found %d brightness levels\n", count - 2));
923         kfree(obj);
924         return result;
925 
926 out_free_levels:
927         kfree(br->levels);
928 out_free:
929         kfree(br);
930 out:
931         device->brightness = NULL;
932         kfree(obj);
933         return result;
934 }
935 
936 /*
937  *  Arg:
938  *      device  : video output device (LCD, CRT, ..)
939  *
940  *  Return Value:
941  *      None
942  *
943  *  Find out all required AML methods defined under the output
944  *  device.
945  */
946 
947 static void acpi_video_device_find_cap(struct acpi_video_device *device)
948 {
949         if (acpi_has_method(device->dev->handle, "_ADR"))
950                 device->cap._ADR = 1;
951         if (acpi_has_method(device->dev->handle, "_BCL"))
952                 device->cap._BCL = 1;
953         if (acpi_has_method(device->dev->handle, "_BCM"))
954                 device->cap._BCM = 1;
955         if (acpi_has_method(device->dev->handle, "_BQC")) {
956                 device->cap._BQC = 1;
957         } else if (acpi_has_method(device->dev->handle, "_BCQ")) {
958                 printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
959                 device->cap._BCQ = 1;
960         }
961 
962         if (acpi_has_method(device->dev->handle, "_DDC"))
963                 device->cap._DDC = 1;
964 }
965 
966 /*
967  *  Arg:
968  *      device  : video output device (VGA)
969  *
970  *  Return Value:
971  *      None
972  *
973  *  Find out all required AML methods defined under the video bus device.
974  */
975 
976 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
977 {
978         if (acpi_has_method(video->device->handle, "_DOS"))
979                 video->cap._DOS = 1;
980         if (acpi_has_method(video->device->handle, "_DOD"))
981                 video->cap._DOD = 1;
982         if (acpi_has_method(video->device->handle, "_ROM"))
983                 video->cap._ROM = 1;
984         if (acpi_has_method(video->device->handle, "_GPD"))
985                 video->cap._GPD = 1;
986         if (acpi_has_method(video->device->handle, "_SPD"))
987                 video->cap._SPD = 1;
988         if (acpi_has_method(video->device->handle, "_VPO"))
989                 video->cap._VPO = 1;
990 }
991 
992 /*
993  * Check whether the video bus device has required AML method to
994  * support the desired features
995  */
996 
997 static int acpi_video_bus_check(struct acpi_video_bus *video)
998 {
999         acpi_status status = -ENOENT;
1000         struct pci_dev *dev;
1001 
1002         if (!video)
1003                 return -EINVAL;
1004 
1005         dev = acpi_get_pci_dev(video->device->handle);
1006         if (!dev)
1007                 return -ENODEV;
1008         pci_dev_put(dev);
1009 
1010         /*
1011          * Since there is no HID, CID and so on for VGA driver, we have
1012          * to check well known required nodes.
1013          */
1014 
1015         /* Does this device support video switching? */
1016         if (video->cap._DOS || video->cap._DOD) {
1017                 if (!video->cap._DOS) {
1018                         printk(KERN_WARNING FW_BUG
1019                                 "ACPI(%s) defines _DOD but not _DOS\n",
1020                                 acpi_device_bid(video->device));
1021                 }
1022                 video->flags.multihead = 1;
1023                 status = 0;
1024         }
1025 
1026         /* Does this device support retrieving a video ROM? */
1027         if (video->cap._ROM) {
1028                 video->flags.rom = 1;
1029                 status = 0;
1030         }
1031 
1032         /* Does this device support configuring which video device to POST? */
1033         if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1034                 video->flags.post = 1;
1035                 status = 0;
1036         }
1037 
1038         return status;
1039 }
1040 
1041 /*
1042  * --------------------------------------------------------------------------
1043  *                               Driver Interface
1044  * --------------------------------------------------------------------------
1045  */
1046 
1047 /* device interface */
1048 static struct acpi_video_device_attrib *
1049 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1050 {
1051         struct acpi_video_enumerated_device *ids;
1052         int i;
1053 
1054         for (i = 0; i < video->attached_count; i++) {
1055                 ids = &video->attached_array[i];
1056                 if ((ids->value.int_val & 0xffff) == device_id)
1057                         return &ids->value.attrib;
1058         }
1059 
1060         return NULL;
1061 }
1062 
1063 static int
1064 acpi_video_get_device_type(struct acpi_video_bus *video,
1065                            unsigned long device_id)
1066 {
1067         struct acpi_video_enumerated_device *ids;
1068         int i;
1069 
1070         for (i = 0; i < video->attached_count; i++) {
1071                 ids = &video->attached_array[i];
1072                 if ((ids->value.int_val & 0xffff) == device_id)
1073                         return ids->value.int_val;
1074         }
1075 
1076         return 0;
1077 }
1078 
1079 static int
1080 acpi_video_bus_get_one_device(struct acpi_device *device,
1081                               struct acpi_video_bus *video)
1082 {
1083         unsigned long long device_id;
1084         int status, device_type;
1085         struct acpi_video_device *data;
1086         struct acpi_video_device_attrib *attribute;
1087 
1088         status =
1089             acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1090         /* Some device omits _ADR, we skip them instead of fail */
1091         if (ACPI_FAILURE(status))
1092                 return 0;
1093 
1094         data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1095         if (!data)
1096                 return -ENOMEM;
1097 
1098         strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1099         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1100         device->driver_data = data;
1101 
1102         data->device_id = device_id;
1103         data->video = video;
1104         data->dev = device;
1105         INIT_DELAYED_WORK(&data->switch_brightness_work,
1106                           acpi_video_switch_brightness);
1107 
1108         attribute = acpi_video_get_device_attr(video, device_id);
1109 
1110         if (attribute && attribute->device_id_scheme) {
1111                 switch (attribute->display_type) {
1112                 case ACPI_VIDEO_DISPLAY_CRT:
1113                         data->flags.crt = 1;
1114                         break;
1115                 case ACPI_VIDEO_DISPLAY_TV:
1116                         data->flags.tvout = 1;
1117                         break;
1118                 case ACPI_VIDEO_DISPLAY_DVI:
1119                         data->flags.dvi = 1;
1120                         break;
1121                 case ACPI_VIDEO_DISPLAY_LCD:
1122                         data->flags.lcd = 1;
1123                         break;
1124                 default:
1125                         data->flags.unknown = 1;
1126                         break;
1127                 }
1128                 if (attribute->bios_can_detect)
1129                         data->flags.bios = 1;
1130         } else {
1131                 /* Check for legacy IDs */
1132                 device_type = acpi_video_get_device_type(video, device_id);
1133                 /* Ignore bits 16 and 18-20 */
1134                 switch (device_type & 0xffe2ffff) {
1135                 case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1136                         data->flags.crt = 1;
1137                         break;
1138                 case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1139                         data->flags.lcd = 1;
1140                         break;
1141                 case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1142                         data->flags.tvout = 1;
1143                         break;
1144                 default:
1145                         data->flags.unknown = 1;
1146                 }
1147         }
1148 
1149         acpi_video_device_bind(video, data);
1150         acpi_video_device_find_cap(data);
1151 
1152         mutex_lock(&video->device_list_lock);
1153         list_add_tail(&data->entry, &video->video_device_list);
1154         mutex_unlock(&video->device_list_lock);
1155 
1156         return status;
1157 }
1158 
1159 /*
1160  *  Arg:
1161  *      video   : video bus device
1162  *
1163  *  Return:
1164  *      none
1165  *
1166  *  Enumerate the video device list of the video bus,
1167  *  bind the ids with the corresponding video devices
1168  *  under the video bus.
1169  */
1170 
1171 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1172 {
1173         struct acpi_video_device *dev;
1174 
1175         mutex_lock(&video->device_list_lock);
1176 
1177         list_for_each_entry(dev, &video->video_device_list, entry)
1178                 acpi_video_device_bind(video, dev);
1179 
1180         mutex_unlock(&video->device_list_lock);
1181 }
1182 
1183 /*
1184  *  Arg:
1185  *      video   : video bus device
1186  *      device  : video output device under the video
1187  *              bus
1188  *
1189  *  Return:
1190  *      none
1191  *
1192  *  Bind the ids with the corresponding video devices
1193  *  under the video bus.
1194  */
1195 
1196 static void
1197 acpi_video_device_bind(struct acpi_video_bus *video,
1198                        struct acpi_video_device *device)
1199 {
1200         struct acpi_video_enumerated_device *ids;
1201         int i;
1202 
1203         for (i = 0; i < video->attached_count; i++) {
1204                 ids = &video->attached_array[i];
1205                 if (device->device_id == (ids->value.int_val & 0xffff)) {
1206                         ids->bind_info = device;
1207                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1208                 }
1209         }
1210 }
1211 
1212 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1213 {
1214         struct acpi_video_bus *video = device->video;
1215         int i;
1216 
1217         /*
1218          * If we have a broken _DOD or we have more than 8 output devices
1219          * under the graphics controller node that we can't proper deal with
1220          * in the operation region code currently, no need to test.
1221          */
1222         if (!video->attached_count || video->child_count > 8)
1223                 return true;
1224 
1225         for (i = 0; i < video->attached_count; i++) {
1226                 if ((video->attached_array[i].value.int_val & 0xfff) ==
1227                     (device->device_id & 0xfff))
1228                         return true;
1229         }
1230 
1231         return false;
1232 }
1233 
1234 /*
1235  *  Arg:
1236  *      video   : video bus device
1237  *
1238  *  Return:
1239  *      < 0     : error
1240  *
1241  *  Call _DOD to enumerate all devices attached to display adapter
1242  *
1243  */
1244 
1245 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1246 {
1247         int status;
1248         int count;
1249         int i;
1250         struct acpi_video_enumerated_device *active_list;
1251         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1252         union acpi_object *dod = NULL;
1253         union acpi_object *obj;
1254 
1255         status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1256         if (!ACPI_SUCCESS(status)) {
1257                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1258                 return status;
1259         }
1260 
1261         dod = buffer.pointer;
1262         if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1263                 ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1264                 status = -EFAULT;
1265                 goto out;
1266         }
1267 
1268         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1269                           dod->package.count));
1270 
1271         active_list = kcalloc(1 + dod->package.count,
1272                               sizeof(struct acpi_video_enumerated_device),
1273                               GFP_KERNEL);
1274         if (!active_list) {
1275                 status = -ENOMEM;
1276                 goto out;
1277         }
1278 
1279         count = 0;
1280         for (i = 0; i < dod->package.count; i++) {
1281                 obj = &dod->package.elements[i];
1282 
1283                 if (obj->type != ACPI_TYPE_INTEGER) {
1284                         printk(KERN_ERR PREFIX
1285                                 "Invalid _DOD data in element %d\n", i);
1286                         continue;
1287                 }
1288 
1289                 active_list[count].value.int_val = obj->integer.value;
1290                 active_list[count].bind_info = NULL;
1291                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1292                                   (int)obj->integer.value));
1293                 count++;
1294         }
1295 
1296         kfree(video->attached_array);
1297 
1298         video->attached_array = active_list;
1299         video->attached_count = count;
1300 
1301 out:
1302         kfree(buffer.pointer);
1303         return status;
1304 }
1305 
1306 static int
1307 acpi_video_get_next_level(struct acpi_video_device *device,
1308                           u32 level_current, u32 event)
1309 {
1310         int min, max, min_above, max_below, i, l, delta = 255;
1311         max = max_below = 0;
1312         min = min_above = 255;
1313         /* Find closest level to level_current */
1314         for (i = 2; i < device->brightness->count; i++) {
1315                 l = device->brightness->levels[i];
1316                 if (abs(l - level_current) < abs(delta)) {
1317                         delta = l - level_current;
1318                         if (!delta)
1319                                 break;
1320                 }
1321         }
1322         /* Ajust level_current to closest available level */
1323         level_current += delta;
1324         for (i = 2; i < device->brightness->count; i++) {
1325                 l = device->brightness->levels[i];
1326                 if (l < min)
1327                         min = l;
1328                 if (l > max)
1329                         max = l;
1330                 if (l < min_above && l > level_current)
1331                         min_above = l;
1332                 if (l > max_below && l < level_current)
1333                         max_below = l;
1334         }
1335 
1336         switch (event) {
1337         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1338                 return (level_current < max) ? min_above : min;
1339         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1340                 return (level_current < max) ? min_above : max;
1341         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1342                 return (level_current > min) ? max_below : min;
1343         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1344         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1345                 return 0;
1346         default:
1347                 return level_current;
1348         }
1349 }
1350 
1351 static void
1352 acpi_video_switch_brightness(struct work_struct *work)
1353 {
1354         struct acpi_video_device *device = container_of(to_delayed_work(work),
1355                              struct acpi_video_device, switch_brightness_work);
1356         unsigned long long level_current, level_next;
1357         int event = device->switch_brightness_event;
1358         int result = -EINVAL;
1359 
1360         /* no warning message if acpi_backlight=vendor or a quirk is used */
1361         if (!acpi_video_verify_backlight_support())
1362                 return;
1363 
1364         if (!device->brightness)
1365                 goto out;
1366 
1367         result = acpi_video_device_lcd_get_level_current(device,
1368                                                          &level_current,
1369                                                          false);
1370         if (result)
1371                 goto out;
1372 
1373         level_next = acpi_video_get_next_level(device, level_current, event);
1374 
1375         result = acpi_video_device_lcd_set_level(device, level_next);
1376 
1377         if (!result)
1378                 backlight_force_update(device->backlight,
1379                                        BACKLIGHT_UPDATE_HOTKEY);
1380 
1381 out:
1382         if (result)
1383                 printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1384 }
1385 
1386 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1387                         void **edid)
1388 {
1389         struct acpi_video_bus *video;
1390         struct acpi_video_device *video_device;
1391         union acpi_object *buffer = NULL;
1392         acpi_status status;
1393         int i, length;
1394 
1395         if (!device || !acpi_driver_data(device))
1396                 return -EINVAL;
1397 
1398         video = acpi_driver_data(device);
1399 
1400         for (i = 0; i < video->attached_count; i++) {
1401                 video_device = video->attached_array[i].bind_info;
1402                 length = 256;
1403 
1404                 if (!video_device)
1405                         continue;
1406 
1407                 if (!video_device->cap._DDC)
1408                         continue;
1409 
1410                 if (type) {
1411                         switch (type) {
1412                         case ACPI_VIDEO_DISPLAY_CRT:
1413                                 if (!video_device->flags.crt)
1414                                         continue;
1415                                 break;
1416                         case ACPI_VIDEO_DISPLAY_TV:
1417                                 if (!video_device->flags.tvout)
1418                                         continue;
1419                                 break;
1420                         case ACPI_VIDEO_DISPLAY_DVI:
1421                                 if (!video_device->flags.dvi)
1422                                         continue;
1423                                 break;
1424                         case ACPI_VIDEO_DISPLAY_LCD:
1425                                 if (!video_device->flags.lcd)
1426                                         continue;
1427                                 break;
1428                         }
1429                 } else if (video_device->device_id != device_id) {
1430                         continue;
1431                 }
1432 
1433                 status = acpi_video_device_EDID(video_device, &buffer, length);
1434 
1435                 if (ACPI_FAILURE(status) || !buffer ||
1436                     buffer->type != ACPI_TYPE_BUFFER) {
1437                         length = 128;
1438                         status = acpi_video_device_EDID(video_device, &buffer,
1439                                                         length);
1440                         if (ACPI_FAILURE(status) || !buffer ||
1441                             buffer->type != ACPI_TYPE_BUFFER) {
1442                                 continue;
1443                         }
1444                 }
1445 
1446                 *edid = buffer->buffer.pointer;
1447                 return length;
1448         }
1449 
1450         return -ENODEV;
1451 }
1452 EXPORT_SYMBOL(acpi_video_get_edid);
1453 
1454 static int
1455 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1456                            struct acpi_device *device)
1457 {
1458         int status = 0;
1459         struct acpi_device *dev;
1460 
1461         /*
1462          * There are systems where video module known to work fine regardless
1463          * of broken _DOD and ignoring returned value here doesn't cause
1464          * any issues later.
1465          */
1466         acpi_video_device_enumerate(video);
1467 
1468         list_for_each_entry(dev, &device->children, node) {
1469 
1470                 status = acpi_video_bus_get_one_device(dev, video);
1471                 if (status) {
1472                         dev_err(&dev->dev, "Can't attach device\n");
1473                         break;
1474                 }
1475                 video->child_count++;
1476         }
1477         return status;
1478 }
1479 
1480 /* acpi_video interface */
1481 
1482 /*
1483  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1484  * preform any automatic brightness change on receiving a notification.
1485  */
1486 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1487 {
1488         return acpi_video_bus_DOS(video, 0,
1489                                   acpi_osi_is_win8() ? 1 : 0);
1490 }
1491 
1492 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1493 {
1494         return acpi_video_bus_DOS(video, 0,
1495                                   acpi_osi_is_win8() ? 0 : 1);
1496 }
1497 
1498 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1499 {
1500         struct acpi_video_bus *video = acpi_driver_data(device);
1501         struct input_dev *input;
1502         int keycode = 0;
1503 
1504         if (!video || !video->input)
1505                 return;
1506 
1507         input = video->input;
1508 
1509         switch (event) {
1510         case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
1511                                          * most likely via hotkey. */
1512                 keycode = KEY_SWITCHVIDEOMODE;
1513                 break;
1514 
1515         case ACPI_VIDEO_NOTIFY_PROBE:   /* User plugged in or removed a video
1516                                          * connector. */
1517                 acpi_video_device_enumerate(video);
1518                 acpi_video_device_rebind(video);
1519                 keycode = KEY_SWITCHVIDEOMODE;
1520                 break;
1521 
1522         case ACPI_VIDEO_NOTIFY_CYCLE:   /* Cycle Display output hotkey pressed. */
1523                 keycode = KEY_SWITCHVIDEOMODE;
1524                 break;
1525         case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:     /* Next Display output hotkey pressed. */
1526                 keycode = KEY_VIDEO_NEXT;
1527                 break;
1528         case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:     /* previous Display output hotkey pressed. */
1529                 keycode = KEY_VIDEO_PREV;
1530                 break;
1531 
1532         default:
1533                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1534                                   "Unsupported event [0x%x]\n", event));
1535                 break;
1536         }
1537 
1538         if (acpi_notifier_call_chain(device, event, 0))
1539                 /* Something vetoed the keypress. */
1540                 keycode = 0;
1541 
1542         if (keycode) {
1543                 input_report_key(input, keycode, 1);
1544                 input_sync(input);
1545                 input_report_key(input, keycode, 0);
1546                 input_sync(input);
1547         }
1548 
1549         return;
1550 }
1551 
1552 static void brightness_switch_event(struct acpi_video_device *video_device,
1553                                     u32 event)
1554 {
1555         if (!brightness_switch_enabled)
1556                 return;
1557 
1558         video_device->switch_brightness_event = event;
1559         schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1560 }
1561 
1562 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1563 {
1564         struct acpi_video_device *video_device = data;
1565         struct acpi_device *device = NULL;
1566         struct acpi_video_bus *bus;
1567         struct input_dev *input;
1568         int keycode = 0;
1569 
1570         if (!video_device)
1571                 return;
1572 
1573         device = video_device->dev;
1574         bus = video_device->video;
1575         input = bus->input;
1576 
1577         switch (event) {
1578         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:        /* Cycle brightness */
1579                 brightness_switch_event(video_device, event);
1580                 keycode = KEY_BRIGHTNESS_CYCLE;
1581                 break;
1582         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
1583                 brightness_switch_event(video_device, event);
1584                 keycode = KEY_BRIGHTNESSUP;
1585                 break;
1586         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
1587                 brightness_switch_event(video_device, event);
1588                 keycode = KEY_BRIGHTNESSDOWN;
1589                 break;
1590         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
1591                 brightness_switch_event(video_device, event);
1592                 keycode = KEY_BRIGHTNESS_ZERO;
1593                 break;
1594         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
1595                 brightness_switch_event(video_device, event);
1596                 keycode = KEY_DISPLAY_OFF;
1597                 break;
1598         default:
1599                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1600                                   "Unsupported event [0x%x]\n", event));
1601                 break;
1602         }
1603 
1604         acpi_notifier_call_chain(device, event, 0);
1605 
1606         if (keycode) {
1607                 input_report_key(input, keycode, 1);
1608                 input_sync(input);
1609                 input_report_key(input, keycode, 0);
1610                 input_sync(input);
1611         }
1612 
1613         return;
1614 }
1615 
1616 static int acpi_video_resume(struct notifier_block *nb,
1617                                 unsigned long val, void *ign)
1618 {
1619         struct acpi_video_bus *video;
1620         struct acpi_video_device *video_device;
1621         int i;
1622 
1623         switch (val) {
1624         case PM_HIBERNATION_PREPARE:
1625         case PM_SUSPEND_PREPARE:
1626         case PM_RESTORE_PREPARE:
1627                 return NOTIFY_DONE;
1628         }
1629 
1630         video = container_of(nb, struct acpi_video_bus, pm_nb);
1631 
1632         dev_info(&video->device->dev, "Restoring backlight state\n");
1633 
1634         for (i = 0; i < video->attached_count; i++) {
1635                 video_device = video->attached_array[i].bind_info;
1636                 if (video_device && video_device->backlight)
1637                         acpi_video_set_brightness(video_device->backlight);
1638         }
1639 
1640         return NOTIFY_OK;
1641 }
1642 
1643 static acpi_status
1644 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1645                         void **return_value)
1646 {
1647         struct acpi_device *device = context;
1648         struct acpi_device *sibling;
1649         int result;
1650 
1651         if (handle == device->handle)
1652                 return AE_CTRL_TERMINATE;
1653 
1654         result = acpi_bus_get_device(handle, &sibling);
1655         if (result)
1656                 return AE_OK;
1657 
1658         if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1659                         return AE_ALREADY_EXISTS;
1660 
1661         return AE_OK;
1662 }
1663 
1664 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1665 {
1666         struct backlight_properties props;
1667         struct pci_dev *pdev;
1668         acpi_handle acpi_parent;
1669         struct device *parent = NULL;
1670         int result;
1671         static int count;
1672         char *name;
1673 
1674         /*
1675          * Do not create backlight device for video output
1676          * device that is not in the enumerated list.
1677          */
1678         if (!acpi_video_device_in_dod(device)) {
1679                 dev_dbg(&device->dev->dev, "not in _DOD list, ignore\n");
1680                 return;
1681         }
1682 
1683         result = acpi_video_init_brightness(device);
1684         if (result)
1685                 return;
1686         name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1687         if (!name)
1688                 return;
1689         count++;
1690 
1691         acpi_get_parent(device->dev->handle, &acpi_parent);
1692 
1693         pdev = acpi_get_pci_dev(acpi_parent);
1694         if (pdev) {
1695                 parent = &pdev->dev;
1696                 pci_dev_put(pdev);
1697         }
1698 
1699         memset(&props, 0, sizeof(struct backlight_properties));
1700         props.type = BACKLIGHT_FIRMWARE;
1701         props.max_brightness = device->brightness->count - 3;
1702         device->backlight = backlight_device_register(name,
1703                                                       parent,
1704                                                       device,
1705                                                       &acpi_backlight_ops,
1706                                                       &props);
1707         kfree(name);
1708         if (IS_ERR(device->backlight))
1709                 return;
1710 
1711         /*
1712          * Save current brightness level in case we have to restore it
1713          * before acpi_video_device_lcd_set_level() is called next time.
1714          */
1715         device->backlight->props.brightness =
1716                         acpi_video_get_brightness(device->backlight);
1717 
1718         device->cooling_dev = thermal_cooling_device_register("LCD",
1719                                 device->dev, &video_cooling_ops);
1720         if (IS_ERR(device->cooling_dev)) {
1721                 /*
1722                  * Set cooling_dev to NULL so we don't crash trying to free it.
1723                  * Also, why the hell we are returning early and not attempt to
1724                  * register video output if cooling device registration failed?
1725                  * -- dtor
1726                  */
1727                 device->cooling_dev = NULL;
1728                 return;
1729         }
1730 
1731         dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1732                  device->cooling_dev->id);
1733         result = sysfs_create_link(&device->dev->dev.kobj,
1734                         &device->cooling_dev->device.kobj,
1735                         "thermal_cooling");
1736         if (result)
1737                 printk(KERN_ERR PREFIX "Create sysfs link\n");
1738         result = sysfs_create_link(&device->cooling_dev->device.kobj,
1739                         &device->dev->dev.kobj, "device");
1740         if (result)
1741                 printk(KERN_ERR PREFIX "Create sysfs link\n");
1742 }
1743 
1744 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1745 {
1746         struct acpi_video_device *dev;
1747         union acpi_object *levels;
1748 
1749         mutex_lock(&video->device_list_lock);
1750         list_for_each_entry(dev, &video->video_device_list, entry) {
1751                 if (!acpi_video_device_lcd_query_levels(dev, &levels))
1752                         kfree(levels);
1753         }
1754         mutex_unlock(&video->device_list_lock);
1755 }
1756 
1757 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1758 {
1759         struct acpi_video_device *dev;
1760 
1761         if (video->backlight_registered)
1762                 return 0;
1763 
1764         acpi_video_run_bcl_for_osi(video);
1765 
1766         if (!acpi_video_verify_backlight_support())
1767                 return 0;
1768 
1769         mutex_lock(&video->device_list_lock);
1770         list_for_each_entry(dev, &video->video_device_list, entry)
1771                 acpi_video_dev_register_backlight(dev);
1772         mutex_unlock(&video->device_list_lock);
1773 
1774         video->backlight_registered = true;
1775 
1776         video->pm_nb.notifier_call = acpi_video_resume;
1777         video->pm_nb.priority = 0;
1778         return register_pm_notifier(&video->pm_nb);
1779 }
1780 
1781 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1782 {
1783         if (device->backlight) {
1784                 backlight_device_unregister(device->backlight);
1785                 device->backlight = NULL;
1786         }
1787         if (device->brightness) {
1788                 kfree(device->brightness->levels);
1789                 kfree(device->brightness);
1790                 device->brightness = NULL;
1791         }
1792         if (device->cooling_dev) {
1793                 sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1794                 sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1795                 thermal_cooling_device_unregister(device->cooling_dev);
1796                 device->cooling_dev = NULL;
1797         }
1798 }
1799 
1800 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1801 {
1802         struct acpi_video_device *dev;
1803         int error;
1804 
1805         if (!video->backlight_registered)
1806                 return 0;
1807 
1808         error = unregister_pm_notifier(&video->pm_nb);
1809 
1810         mutex_lock(&video->device_list_lock);
1811         list_for_each_entry(dev, &video->video_device_list, entry)
1812                 acpi_video_dev_unregister_backlight(dev);
1813         mutex_unlock(&video->device_list_lock);
1814 
1815         video->backlight_registered = false;
1816 
1817         return error;
1818 }
1819 
1820 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1821 {
1822         acpi_status status;
1823         struct acpi_device *adev = device->dev;
1824 
1825         status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1826                                              acpi_video_device_notify, device);
1827         if (ACPI_FAILURE(status))
1828                 dev_err(&adev->dev, "Error installing notify handler\n");
1829         else
1830                 device->flags.notify = 1;
1831 }
1832 
1833 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1834 {
1835         struct input_dev *input;
1836         struct acpi_video_device *dev;
1837         int error;
1838 
1839         video->input = input = input_allocate_device();
1840         if (!input) {
1841                 error = -ENOMEM;
1842                 goto out;
1843         }
1844 
1845         error = acpi_video_bus_start_devices(video);
1846         if (error)
1847                 goto err_free_input;
1848 
1849         snprintf(video->phys, sizeof(video->phys),
1850                         "%s/video/input0", acpi_device_hid(video->device));
1851 
1852         input->name = acpi_device_name(video->device);
1853         input->phys = video->phys;
1854         input->id.bustype = BUS_HOST;
1855         input->id.product = 0x06;
1856         input->dev.parent = &video->device->dev;
1857         input->evbit[0] = BIT(EV_KEY);
1858         set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1859         set_bit(KEY_VIDEO_NEXT, input->keybit);
1860         set_bit(KEY_VIDEO_PREV, input->keybit);
1861         set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1862         set_bit(KEY_BRIGHTNESSUP, input->keybit);
1863         set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1864         set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1865         set_bit(KEY_DISPLAY_OFF, input->keybit);
1866 
1867         error = input_register_device(input);
1868         if (error)
1869                 goto err_stop_dev;
1870 
1871         mutex_lock(&video->device_list_lock);
1872         list_for_each_entry(dev, &video->video_device_list, entry)
1873                 acpi_video_dev_add_notify_handler(dev);
1874         mutex_unlock(&video->device_list_lock);
1875 
1876         return 0;
1877 
1878 err_stop_dev:
1879         acpi_video_bus_stop_devices(video);
1880 err_free_input:
1881         input_free_device(input);
1882         video->input = NULL;
1883 out:
1884         return error;
1885 }
1886 
1887 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1888 {
1889         if (dev->flags.notify) {
1890                 acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1891                                            acpi_video_device_notify);
1892                 dev->flags.notify = 0;
1893         }
1894 }
1895 
1896 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1897 {
1898         struct acpi_video_device *dev;
1899 
1900         mutex_lock(&video->device_list_lock);
1901         list_for_each_entry(dev, &video->video_device_list, entry)
1902                 acpi_video_dev_remove_notify_handler(dev);
1903         mutex_unlock(&video->device_list_lock);
1904 
1905         acpi_video_bus_stop_devices(video);
1906         input_unregister_device(video->input);
1907         video->input = NULL;
1908 }
1909 
1910 static int acpi_video_backlight_notify(struct notifier_block *nb,
1911                                         unsigned long val, void *bd)
1912 {
1913         struct backlight_device *backlight = bd;
1914         struct acpi_video_bus *video;
1915 
1916         /* acpi_video_verify_backlight_support only cares about raw devices */
1917         if (backlight->props.type != BACKLIGHT_RAW)
1918                 return NOTIFY_DONE;
1919 
1920         video = container_of(nb, struct acpi_video_bus, backlight_nb);
1921 
1922         switch (val) {
1923         case BACKLIGHT_REGISTERED:
1924                 if (!acpi_video_verify_backlight_support())
1925                         acpi_video_bus_unregister_backlight(video);
1926                 break;
1927         case BACKLIGHT_UNREGISTERED:
1928                 acpi_video_bus_register_backlight(video);
1929                 break;
1930         }
1931 
1932         return NOTIFY_OK;
1933 }
1934 
1935 static int acpi_video_bus_add_backlight_notify_handler(
1936                                                 struct acpi_video_bus *video)
1937 {
1938         int error;
1939 
1940         video->backlight_nb.notifier_call = acpi_video_backlight_notify;
1941         video->backlight_nb.priority = 0;
1942         error = backlight_register_notifier(&video->backlight_nb);
1943         if (error == 0)
1944                 video->backlight_notifier_registered = true;
1945 
1946         return error;
1947 }
1948 
1949 static int acpi_video_bus_remove_backlight_notify_handler(
1950                                                 struct acpi_video_bus *video)
1951 {
1952         if (!video->backlight_notifier_registered)
1953                 return 0;
1954 
1955         video->backlight_notifier_registered = false;
1956 
1957         return backlight_unregister_notifier(&video->backlight_nb);
1958 }
1959 
1960 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1961 {
1962         struct acpi_video_device *dev, *next;
1963 
1964         mutex_lock(&video->device_list_lock);
1965         list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1966                 list_del(&dev->entry);
1967                 kfree(dev);
1968         }
1969         mutex_unlock(&video->device_list_lock);
1970 
1971         return 0;
1972 }
1973 
1974 static int instance;
1975 
1976 static int acpi_video_bus_add(struct acpi_device *device)
1977 {
1978         struct acpi_video_bus *video;
1979         int error;
1980         acpi_status status;
1981 
1982         status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1983                                 device->parent->handle, 1,
1984                                 acpi_video_bus_match, NULL,
1985                                 device, NULL);
1986         if (status == AE_ALREADY_EXISTS) {
1987                 printk(KERN_WARNING FW_BUG
1988                         "Duplicate ACPI video bus devices for the"
1989                         " same VGA controller, please try module "
1990                         "parameter \"video.allow_duplicates=1\""
1991                         "if the current driver doesn't work.\n");
1992                 if (!allow_duplicates)
1993                         return -ENODEV;
1994         }
1995 
1996         video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1997         if (!video)
1998                 return -ENOMEM;
1999 
2000         /* a hack to fix the duplicate name "VID" problem on T61 */
2001         if (!strcmp(device->pnp.bus_id, "VID")) {
2002                 if (instance)
2003                         device->pnp.bus_id[3] = '' + instance;
2004                 instance++;
2005         }
2006         /* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2007         if (!strcmp(device->pnp.bus_id, "VGA")) {
2008                 if (instance)
2009                         device->pnp.bus_id[3] = '' + instance;
2010                 instance++;
2011         }
2012 
2013         video->device = device;
2014         strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2015         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2016         device->driver_data = video;
2017 
2018         acpi_video_bus_find_cap(video);
2019         error = acpi_video_bus_check(video);
2020         if (error)
2021                 goto err_free_video;
2022 
2023         mutex_init(&video->device_list_lock);
2024         INIT_LIST_HEAD(&video->video_device_list);
2025 
2026         error = acpi_video_bus_get_devices(video, device);
2027         if (error)
2028                 goto err_put_video;
2029 
2030         printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2031                ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2032                video->flags.multihead ? "yes" : "no",
2033                video->flags.rom ? "yes" : "no",
2034                video->flags.post ? "yes" : "no");
2035         mutex_lock(&video_list_lock);
2036         list_add_tail(&video->entry, &video_bus_head);
2037         mutex_unlock(&video_list_lock);
2038 
2039         acpi_video_bus_register_backlight(video);
2040         acpi_video_bus_add_notify_handler(video);
2041         acpi_video_bus_add_backlight_notify_handler(video);
2042 
2043         return 0;
2044 
2045 err_put_video:
2046         acpi_video_bus_put_devices(video);
2047         kfree(video->attached_array);
2048 err_free_video:
2049         kfree(video);
2050         device->driver_data = NULL;
2051 
2052         return error;
2053 }
2054 
2055 static int acpi_video_bus_remove(struct acpi_device *device)
2056 {
2057         struct acpi_video_bus *video = NULL;
2058 
2059 
2060         if (!device || !acpi_driver_data(device))
2061                 return -EINVAL;
2062 
2063         video = acpi_driver_data(device);
2064 
2065         acpi_video_bus_remove_backlight_notify_handler(video);
2066         acpi_video_bus_remove_notify_handler(video);
2067         acpi_video_bus_unregister_backlight(video);
2068         acpi_video_bus_put_devices(video);
2069 
2070         mutex_lock(&video_list_lock);
2071         list_del(&video->entry);
2072         mutex_unlock(&video_list_lock);
2073 
2074         kfree(video->attached_array);
2075         kfree(video);
2076 
2077         return 0;
2078 }
2079 
2080 static int __init is_i740(struct pci_dev *dev)
2081 {
2082         if (dev->device == 0x00D1)
2083                 return 1;
2084         if (dev->device == 0x7000)
2085                 return 1;
2086         return 0;
2087 }
2088 
2089 static int __init intel_opregion_present(void)
2090 {
2091         int opregion = 0;
2092         struct pci_dev *dev = NULL;
2093         u32 address;
2094 
2095         for_each_pci_dev(dev) {
2096                 if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2097                         continue;
2098                 if (dev->vendor != PCI_VENDOR_ID_INTEL)
2099                         continue;
2100                 /* We don't want to poke around undefined i740 registers */
2101                 if (is_i740(dev))
2102                         continue;
2103                 pci_read_config_dword(dev, 0xfc, &address);
2104                 if (!address)
2105                         continue;
2106                 opregion = 1;
2107         }
2108         return opregion;
2109 }
2110 
2111 int acpi_video_register(void)
2112 {
2113         int ret;
2114 
2115         if (register_count) {
2116                 /*
2117                  * if the function of acpi_video_register is already called,
2118                  * don't register the acpi_vide_bus again and return no error.
2119                  */
2120                 return 0;
2121         }
2122 
2123         mutex_init(&video_list_lock);
2124         INIT_LIST_HEAD(&video_bus_head);
2125 
2126         ret = acpi_bus_register_driver(&acpi_video_bus);
2127         if (ret)
2128                 return ret;
2129 
2130         /*
2131          * When the acpi_video_bus is loaded successfully, increase
2132          * the counter reference.
2133          */
2134         register_count = 1;
2135 
2136         return 0;
2137 }
2138 EXPORT_SYMBOL(acpi_video_register);
2139 
2140 void acpi_video_unregister(void)
2141 {
2142         if (!register_count) {
2143                 /*
2144                  * If the acpi video bus is already unloaded, don't
2145                  * unload it again and return directly.
2146                  */
2147                 return;
2148         }
2149         acpi_bus_unregister_driver(&acpi_video_bus);
2150 
2151         register_count = 0;
2152 
2153         return;
2154 }
2155 EXPORT_SYMBOL(acpi_video_unregister);
2156 
2157 void acpi_video_unregister_backlight(void)
2158 {
2159         struct acpi_video_bus *video;
2160 
2161         if (!register_count)
2162                 return;
2163 
2164         mutex_lock(&video_list_lock);
2165         list_for_each_entry(video, &video_bus_head, entry)
2166                 acpi_video_bus_unregister_backlight(video);
2167         mutex_unlock(&video_list_lock);
2168 }
2169 EXPORT_SYMBOL(acpi_video_unregister_backlight);
2170 
2171 /*
2172  * This is kind of nasty. Hardware using Intel chipsets may require
2173  * the video opregion code to be run first in order to initialise
2174  * state before any ACPI video calls are made. To handle this we defer
2175  * registration of the video class until the opregion code has run.
2176  */
2177 
2178 static int __init acpi_video_init(void)
2179 {
2180         /*
2181          * Let the module load even if ACPI is disabled (e.g. due to
2182          * a broken BIOS) so that i915.ko can still be loaded on such
2183          * old systems without an AcpiOpRegion.
2184          *
2185          * acpi_video_register() will report -ENODEV later as well due
2186          * to acpi_disabled when i915.ko tries to register itself afterwards.
2187          */
2188         if (acpi_disabled)
2189                 return 0;
2190 
2191         dmi_check_system(video_dmi_table);
2192 
2193         if (intel_opregion_present())
2194                 return 0;
2195 
2196         return acpi_video_register();
2197 }
2198 
2199 static void __exit acpi_video_exit(void)
2200 {
2201         acpi_video_unregister();
2202 
2203         return;
2204 }
2205 
2206 module_init(acpi_video_init);
2207 module_exit(acpi_video_exit);
2208 

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