Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 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

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

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