Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 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

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 = false;
 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         u8 dos_setting;
154         struct acpi_video_enumerated_device *attached_array;
155         u8 attached_count;
156         struct acpi_video_bus_cap cap;
157         struct acpi_video_bus_flags flags;
158         struct list_head video_device_list;
159         struct mutex device_list_lock;  /* protects video_device_list */
160         struct list_head entry;
161         struct input_dev *input;
162         char phys[32];  /* for input device */
163         struct notifier_block pm_nb;
164 };
165 
166 struct acpi_video_device_flags {
167         u8 crt:1;
168         u8 lcd:1;
169         u8 tvout:1;
170         u8 dvi:1;
171         u8 bios:1;
172         u8 unknown:1;
173         u8 notify:1;
174         u8 reserved:1;
175 };
176 
177 struct acpi_video_device_cap {
178         u8 _ADR:1;              /* Return the unique ID */
179         u8 _BCL:1;              /* Query list of brightness control levels supported */
180         u8 _BCM:1;              /* Set the brightness level */
181         u8 _BQC:1;              /* Get current brightness level */
182         u8 _BCQ:1;              /* Some buggy BIOS uses _BCQ instead of _BQC */
183         u8 _DDC:1;              /* Return the EDID for this device */
184 };
185 
186 struct acpi_video_brightness_flags {
187         u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
188         u8 _BCL_reversed:1;             /* _BCL package is in a reversed order */
189         u8 _BQC_use_index:1;            /* _BQC returns an index value */
190 };
191 
192 struct acpi_video_device_brightness {
193         int curr;
194         int count;
195         int *levels;
196         struct acpi_video_brightness_flags flags;
197 };
198 
199 struct acpi_video_device {
200         unsigned long device_id;
201         struct acpi_video_device_flags flags;
202         struct acpi_video_device_cap cap;
203         struct list_head entry;
204         struct acpi_video_bus *video;
205         struct acpi_device *dev;
206         struct acpi_video_device_brightness *brightness;
207         struct backlight_device *backlight;
208         struct thermal_cooling_device *cooling_dev;
209 };
210 
211 static const char device_decode[][30] = {
212         "motherboard VGA device",
213         "PCI VGA device",
214         "AGP VGA device",
215         "UNKNOWN",
216 };
217 
218 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
219 static void acpi_video_device_rebind(struct acpi_video_bus *video);
220 static void acpi_video_device_bind(struct acpi_video_bus *video,
221                                    struct acpi_video_device *device);
222 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
223 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
224                         int level);
225 static int acpi_video_device_lcd_get_level_current(
226                         struct acpi_video_device *device,
227                         unsigned long long *level, bool raw);
228 static int acpi_video_get_next_level(struct acpi_video_device *device,
229                                      u32 level_current, u32 event);
230 static int acpi_video_switch_brightness(struct acpi_video_device *device,
231                                          int event);
232 
233 static bool acpi_video_use_native_backlight(void)
234 {
235         if (use_native_backlight_param != -1)
236                 return use_native_backlight_param;
237         else
238                 return use_native_backlight_dmi;
239 }
240 
241 static bool acpi_video_verify_backlight_support(void)
242 {
243         if (acpi_osi_is_win8() && acpi_video_use_native_backlight() &&
244             backlight_device_registered(BACKLIGHT_RAW))
245                 return false;
246         return acpi_video_backlight_support();
247 }
248 
249 /* backlight device sysfs support */
250 static int acpi_video_get_brightness(struct backlight_device *bd)
251 {
252         unsigned long long cur_level;
253         int i;
254         struct acpi_video_device *vd = bl_get_data(bd);
255 
256         if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
257                 return -EINVAL;
258         for (i = 2; i < vd->brightness->count; i++) {
259                 if (vd->brightness->levels[i] == cur_level)
260                         /*
261                          * The first two entries are special - see page 575
262                          * of the ACPI spec 3.0
263                          */
264                         return i - 2;
265         }
266         return 0;
267 }
268 
269 static int acpi_video_set_brightness(struct backlight_device *bd)
270 {
271         int request_level = bd->props.brightness + 2;
272         struct acpi_video_device *vd = bl_get_data(bd);
273 
274         return acpi_video_device_lcd_set_level(vd,
275                                 vd->brightness->levels[request_level]);
276 }
277 
278 static const struct backlight_ops acpi_backlight_ops = {
279         .get_brightness = acpi_video_get_brightness,
280         .update_status  = acpi_video_set_brightness,
281 };
282 
283 /* thermal cooling device callbacks */
284 static int video_get_max_state(struct thermal_cooling_device *cooling_dev, unsigned
285                                long *state)
286 {
287         struct acpi_device *device = cooling_dev->devdata;
288         struct acpi_video_device *video = acpi_driver_data(device);
289 
290         *state = video->brightness->count - 3;
291         return 0;
292 }
293 
294 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsigned
295                                long *state)
296 {
297         struct acpi_device *device = cooling_dev->devdata;
298         struct acpi_video_device *video = acpi_driver_data(device);
299         unsigned long long level;
300         int offset;
301 
302         if (acpi_video_device_lcd_get_level_current(video, &level, false))
303                 return -EINVAL;
304         for (offset = 2; offset < video->brightness->count; offset++)
305                 if (level == video->brightness->levels[offset]) {
306                         *state = video->brightness->count - offset - 1;
307                         return 0;
308                 }
309 
310         return -EINVAL;
311 }
312 
313 static int
314 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
315 {
316         struct acpi_device *device = cooling_dev->devdata;
317         struct acpi_video_device *video = acpi_driver_data(device);
318         int level;
319 
320         if (state >= video->brightness->count - 2)
321                 return -EINVAL;
322 
323         state = video->brightness->count - state;
324         level = video->brightness->levels[state - 1];
325         return acpi_video_device_lcd_set_level(video, level);
326 }
327 
328 static const struct thermal_cooling_device_ops video_cooling_ops = {
329         .get_max_state = video_get_max_state,
330         .get_cur_state = video_get_cur_state,
331         .set_cur_state = video_set_cur_state,
332 };
333 
334 /*
335  * --------------------------------------------------------------------------
336  *                             Video Management
337  * --------------------------------------------------------------------------
338  */
339 
340 static int
341 acpi_video_device_lcd_query_levels(struct acpi_video_device *device,
342                                    union acpi_object **levels)
343 {
344         int status;
345         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
346         union acpi_object *obj;
347 
348 
349         *levels = NULL;
350 
351         status = acpi_evaluate_object(device->dev->handle, "_BCL", NULL, &buffer);
352         if (!ACPI_SUCCESS(status))
353                 return status;
354         obj = (union acpi_object *)buffer.pointer;
355         if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
356                 printk(KERN_ERR PREFIX "Invalid _BCL data\n");
357                 status = -EFAULT;
358                 goto err;
359         }
360 
361         *levels = obj;
362 
363         return 0;
364 
365 err:
366         kfree(buffer.pointer);
367 
368         return status;
369 }
370 
371 static int
372 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
373 {
374         int status;
375         int state;
376 
377         status = acpi_execute_simple_method(device->dev->handle,
378                                             "_BCM", level);
379         if (ACPI_FAILURE(status)) {
380                 ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
381                 return -EIO;
382         }
383 
384         device->brightness->curr = level;
385         for (state = 2; state < device->brightness->count; state++)
386                 if (level == device->brightness->levels[state]) {
387                         if (device->backlight)
388                                 device->backlight->props.brightness = state - 2;
389                         return 0;
390                 }
391 
392         ACPI_ERROR((AE_INFO, "Current brightness invalid"));
393         return -EINVAL;
394 }
395 
396 /*
397  * For some buggy _BQC methods, we need to add a constant value to
398  * the _BQC return value to get the actual current brightness level
399  */
400 
401 static int bqc_offset_aml_bug_workaround;
402 static int __init video_set_bqc_offset(const struct dmi_system_id *d)
403 {
404         bqc_offset_aml_bug_workaround = 9;
405         return 0;
406 }
407 
408 static int __init video_set_use_native_backlight(const struct dmi_system_id *d)
409 {
410         use_native_backlight_dmi = true;
411         return 0;
412 }
413 
414 static struct dmi_system_id video_dmi_table[] __initdata = {
415         /*
416          * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
417          */
418         {
419          .callback = video_set_bqc_offset,
420          .ident = "Acer Aspire 5720",
421          .matches = {
422                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
423                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
424                 },
425         },
426         {
427          .callback = video_set_bqc_offset,
428          .ident = "Acer Aspire 5710Z",
429          .matches = {
430                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
431                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
432                 },
433         },
434         {
435          .callback = video_set_bqc_offset,
436          .ident = "eMachines E510",
437          .matches = {
438                 DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
439                 DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
440                 },
441         },
442         {
443          .callback = video_set_bqc_offset,
444          .ident = "Acer Aspire 5315",
445          .matches = {
446                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
447                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
448                 },
449         },
450         {
451          .callback = video_set_bqc_offset,
452          .ident = "Acer Aspire 7720",
453          .matches = {
454                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
455                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
456                 },
457         },
458         {
459          .callback = video_set_use_native_backlight,
460          .ident = "ThinkPad T430 and T430s",
461          .matches = {
462                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
463                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T430"),
464                 },
465         },
466         {
467          .callback = video_set_use_native_backlight,
468          .ident = "ThinkPad X230",
469          .matches = {
470                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
471                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X230"),
472                 },
473         },
474         {
475          .callback = video_set_use_native_backlight,
476         .ident = "ThinkPad X1 Carbon",
477         .matches = {
478                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
479                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X1 Carbon"),
480                 },
481         },
482         {
483          .callback = video_set_use_native_backlight,
484          .ident = "Lenovo Yoga 13",
485          .matches = {
486                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
487                 DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Yoga 13"),
488                 },
489         },
490         {
491         .callback = video_set_use_native_backlight,
492         .ident = "Thinkpad Helix",
493         .matches = {
494                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
495                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad Helix"),
496                 },
497         },
498         {
499          .callback = video_set_use_native_backlight,
500          .ident = "Dell Inspiron 7520",
501          .matches = {
502                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
503                 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7520"),
504                 },
505         },
506         {
507          .callback = video_set_use_native_backlight,
508          .ident = "Acer Aspire 5733Z",
509          .matches = {
510                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
511                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5733Z"),
512                 },
513         },
514         {
515          .callback = video_set_use_native_backlight,
516          .ident = "Acer Aspire 5742G",
517          .matches = {
518                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
519                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5742G"),
520                 },
521         },
522         {
523          .callback = video_set_use_native_backlight,
524          .ident = "Acer Aspire V5-431",
525          .matches = {
526                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
527                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire V5-431"),
528                 },
529         },
530         {
531         .callback = video_set_use_native_backlight,
532         .ident = "HP ProBook 4340s",
533         .matches = {
534                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
535                 DMI_MATCH(DMI_PRODUCT_VERSION, "HP ProBook 4340s"),
536                 },
537         },
538         {
539         .callback = video_set_use_native_backlight,
540         .ident = "HP ProBook 2013 models",
541         .matches = {
542                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
543                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ProBook "),
544                 DMI_MATCH(DMI_PRODUCT_NAME, " G1"),
545                 },
546         },
547         {
548         .callback = video_set_use_native_backlight,
549         .ident = "HP EliteBook 2013 models",
550         .matches = {
551                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
552                 DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook "),
553                 DMI_MATCH(DMI_PRODUCT_NAME, " G1"),
554                 },
555         },
556         {
557         .callback = video_set_use_native_backlight,
558         .ident = "HP ZBook 14",
559         .matches = {
560                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
561                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 14"),
562                 },
563         },
564         {
565         .callback = video_set_use_native_backlight,
566         .ident = "HP ZBook 15",
567         .matches = {
568                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
569                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 15"),
570                 },
571         },
572         {
573         .callback = video_set_use_native_backlight,
574         .ident = "HP ZBook 17",
575         .matches = {
576                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
577                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 17"),
578                 },
579         },
580         {
581         .callback = video_set_use_native_backlight,
582         .ident = "HP EliteBook 8780w",
583         .matches = {
584                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
585                 DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook 8780w"),
586                 },
587         },
588         {}
589 };
590 
591 static unsigned long long
592 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
593                               unsigned long long bqc_value)
594 {
595         unsigned long long level;
596 
597         if (device->brightness->flags._BQC_use_index) {
598                 /*
599                  * _BQC returns an index that doesn't account for
600                  * the first 2 items with special meaning, so we need
601                  * to compensate for that by offsetting ourselves
602                  */
603                 if (device->brightness->flags._BCL_reversed)
604                         bqc_value = device->brightness->count - 3 - bqc_value;
605 
606                 level = device->brightness->levels[bqc_value + 2];
607         } else {
608                 level = bqc_value;
609         }
610 
611         level += bqc_offset_aml_bug_workaround;
612 
613         return level;
614 }
615 
616 static int
617 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
618                                         unsigned long long *level, bool raw)
619 {
620         acpi_status status = AE_OK;
621         int i;
622 
623         if (device->cap._BQC || device->cap._BCQ) {
624                 char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
625 
626                 status = acpi_evaluate_integer(device->dev->handle, buf,
627                                                 NULL, level);
628                 if (ACPI_SUCCESS(status)) {
629                         if (raw) {
630                                 /*
631                                  * Caller has indicated he wants the raw
632                                  * value returned by _BQC, so don't furtherly
633                                  * mess with the value.
634                                  */
635                                 return 0;
636                         }
637 
638                         *level = acpi_video_bqc_value_to_level(device, *level);
639 
640                         for (i = 2; i < device->brightness->count; i++)
641                                 if (device->brightness->levels[i] == *level) {
642                                         device->brightness->curr = *level;
643                                         return 0;
644                                 }
645                         /*
646                          * BQC returned an invalid level.
647                          * Stop using it.
648                          */
649                         ACPI_WARNING((AE_INFO,
650                                       "%s returned an invalid level",
651                                       buf));
652                         device->cap._BQC = device->cap._BCQ = 0;
653                 } else {
654                         /*
655                          * Fixme:
656                          * should we return an error or ignore this failure?
657                          * dev->brightness->curr is a cached value which stores
658                          * the correct current backlight level in most cases.
659                          * ACPI video backlight still works w/ buggy _BQC.
660                          * http://bugzilla.kernel.org/show_bug.cgi?id=12233
661                          */
662                         ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
663                         device->cap._BQC = device->cap._BCQ = 0;
664                 }
665         }
666 
667         *level = device->brightness->curr;
668         return 0;
669 }
670 
671 static int
672 acpi_video_device_EDID(struct acpi_video_device *device,
673                        union acpi_object **edid, ssize_t length)
674 {
675         int status;
676         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
677         union acpi_object *obj;
678         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
679         struct acpi_object_list args = { 1, &arg0 };
680 
681 
682         *edid = NULL;
683 
684         if (!device)
685                 return -ENODEV;
686         if (length == 128)
687                 arg0.integer.value = 1;
688         else if (length == 256)
689                 arg0.integer.value = 2;
690         else
691                 return -EINVAL;
692 
693         status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
694         if (ACPI_FAILURE(status))
695                 return -ENODEV;
696 
697         obj = buffer.pointer;
698 
699         if (obj && obj->type == ACPI_TYPE_BUFFER)
700                 *edid = obj;
701         else {
702                 printk(KERN_ERR PREFIX "Invalid _DDC data\n");
703                 status = -EFAULT;
704                 kfree(obj);
705         }
706 
707         return status;
708 }
709 
710 /* bus */
711 
712 /*
713  *  Arg:
714  *      video           : video bus device pointer
715  *      bios_flag       :
716  *              0.      The system BIOS should NOT automatically switch(toggle)
717  *                      the active display output.
718  *              1.      The system BIOS should automatically switch (toggle) the
719  *                      active display output. No switch event.
720  *              2.      The _DGS value should be locked.
721  *              3.      The system BIOS should not automatically switch (toggle) the
722  *                      active display output, but instead generate the display switch
723  *                      event notify code.
724  *      lcd_flag        :
725  *              0.      The system BIOS should automatically control the brightness level
726  *                      of the LCD when the power changes from AC to DC
727  *              1.      The system BIOS should NOT automatically control the brightness
728  *                      level of the LCD when the power changes from AC to DC.
729  *  Return Value:
730  *              -EINVAL wrong arg.
731  */
732 
733 static int
734 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
735 {
736         acpi_status status;
737 
738         if (!video->cap._DOS)
739                 return 0;
740 
741         if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
742                 return -EINVAL;
743         video->dos_setting = (lcd_flag << 2) | bios_flag;
744         status = acpi_execute_simple_method(video->device->handle, "_DOS",
745                                             (lcd_flag << 2) | bios_flag);
746         if (ACPI_FAILURE(status))
747                 return -EIO;
748 
749         return 0;
750 }
751 
752 /*
753  * Simple comparison function used to sort backlight levels.
754  */
755 
756 static int
757 acpi_video_cmp_level(const void *a, const void *b)
758 {
759         return *(int *)a - *(int *)b;
760 }
761 
762 /*
763  * Decides if _BQC/_BCQ for this system is usable
764  *
765  * We do this by changing the level first and then read out the current
766  * brightness level, if the value does not match, find out if it is using
767  * index. If not, clear the _BQC/_BCQ capability.
768  */
769 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
770                                 int max_level, int current_level)
771 {
772         struct acpi_video_device_brightness *br = device->brightness;
773         int result;
774         unsigned long long level;
775         int test_level;
776 
777         /* don't mess with existing known broken systems */
778         if (bqc_offset_aml_bug_workaround)
779                 return 0;
780 
781         /*
782          * Some systems always report current brightness level as maximum
783          * through _BQC, we need to test another value for them.
784          */
785         test_level = current_level == max_level ? br->levels[3] : max_level;
786 
787         result = acpi_video_device_lcd_set_level(device, test_level);
788         if (result)
789                 return result;
790 
791         result = acpi_video_device_lcd_get_level_current(device, &level, true);
792         if (result)
793                 return result;
794 
795         if (level != test_level) {
796                 /* buggy _BQC found, need to find out if it uses index */
797                 if (level < br->count) {
798                         if (br->flags._BCL_reversed)
799                                 level = br->count - 3 - level;
800                         if (br->levels[level + 2] == test_level)
801                                 br->flags._BQC_use_index = 1;
802                 }
803 
804                 if (!br->flags._BQC_use_index)
805                         device->cap._BQC = device->cap._BCQ = 0;
806         }
807 
808         return 0;
809 }
810 
811 
812 /*
813  *  Arg:
814  *      device  : video output device (LCD, CRT, ..)
815  *
816  *  Return Value:
817  *      Maximum brightness level
818  *
819  *  Allocate and initialize device->brightness.
820  */
821 
822 static int
823 acpi_video_init_brightness(struct acpi_video_device *device)
824 {
825         union acpi_object *obj = NULL;
826         int i, max_level = 0, count = 0, level_ac_battery = 0;
827         unsigned long long level, level_old;
828         union acpi_object *o;
829         struct acpi_video_device_brightness *br = NULL;
830         int result = -EINVAL;
831         u32 value;
832 
833         if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
834                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
835                                                 "LCD brightness level\n"));
836                 goto out;
837         }
838 
839         if (obj->package.count < 2)
840                 goto out;
841 
842         br = kzalloc(sizeof(*br), GFP_KERNEL);
843         if (!br) {
844                 printk(KERN_ERR "can't allocate memory\n");
845                 result = -ENOMEM;
846                 goto out;
847         }
848 
849         br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
850                                 GFP_KERNEL);
851         if (!br->levels) {
852                 result = -ENOMEM;
853                 goto out_free;
854         }
855 
856         for (i = 0; i < obj->package.count; i++) {
857                 o = (union acpi_object *)&obj->package.elements[i];
858                 if (o->type != ACPI_TYPE_INTEGER) {
859                         printk(KERN_ERR PREFIX "Invalid data\n");
860                         continue;
861                 }
862                 value = (u32) o->integer.value;
863                 /* Skip duplicate entries */
864                 if (count > 2 && br->levels[count - 1] == value)
865                         continue;
866 
867                 br->levels[count] = value;
868 
869                 if (br->levels[count] > max_level)
870                         max_level = br->levels[count];
871                 count++;
872         }
873 
874         /*
875          * some buggy BIOS don't export the levels
876          * when machine is on AC/Battery in _BCL package.
877          * In this case, the first two elements in _BCL packages
878          * are also supported brightness levels that OS should take care of.
879          */
880         for (i = 2; i < count; i++) {
881                 if (br->levels[i] == br->levels[0])
882                         level_ac_battery++;
883                 if (br->levels[i] == br->levels[1])
884                         level_ac_battery++;
885         }
886 
887         if (level_ac_battery < 2) {
888                 level_ac_battery = 2 - level_ac_battery;
889                 br->flags._BCL_no_ac_battery_levels = 1;
890                 for (i = (count - 1 + level_ac_battery); i >= 2; i--)
891                         br->levels[i] = br->levels[i - level_ac_battery];
892                 count += level_ac_battery;
893         } else if (level_ac_battery > 2)
894                 ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
895 
896         /* Check if the _BCL package is in a reversed order */
897         if (max_level == br->levels[2]) {
898                 br->flags._BCL_reversed = 1;
899                 sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
900                         acpi_video_cmp_level, NULL);
901         } else if (max_level != br->levels[count - 1])
902                 ACPI_ERROR((AE_INFO,
903                             "Found unordered _BCL package"));
904 
905         br->count = count;
906         device->brightness = br;
907 
908         /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
909         br->curr = level = max_level;
910 
911         if (!device->cap._BQC)
912                 goto set_level;
913 
914         result = acpi_video_device_lcd_get_level_current(device,
915                                                          &level_old, true);
916         if (result)
917                 goto out_free_levels;
918 
919         result = acpi_video_bqc_quirk(device, max_level, level_old);
920         if (result)
921                 goto out_free_levels;
922         /*
923          * cap._BQC may get cleared due to _BQC is found to be broken
924          * in acpi_video_bqc_quirk, so check again here.
925          */
926         if (!device->cap._BQC)
927                 goto set_level;
928 
929         level = acpi_video_bqc_value_to_level(device, level_old);
930         /*
931          * On some buggy laptops, _BQC returns an uninitialized
932          * value when invoked for the first time, i.e.
933          * level_old is invalid (no matter whether it's a level
934          * or an index). Set the backlight to max_level in this case.
935          */
936         for (i = 2; i < br->count; i++)
937                 if (level == br->levels[i])
938                         break;
939         if (i == br->count || !level)
940                 level = max_level;
941 
942 set_level:
943         result = acpi_video_device_lcd_set_level(device, level);
944         if (result)
945                 goto out_free_levels;
946 
947         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
948                           "found %d brightness levels\n", count - 2));
949         kfree(obj);
950         return result;
951 
952 out_free_levels:
953         kfree(br->levels);
954 out_free:
955         kfree(br);
956 out:
957         device->brightness = NULL;
958         kfree(obj);
959         return result;
960 }
961 
962 /*
963  *  Arg:
964  *      device  : video output device (LCD, CRT, ..)
965  *
966  *  Return Value:
967  *      None
968  *
969  *  Find out all required AML methods defined under the output
970  *  device.
971  */
972 
973 static void acpi_video_device_find_cap(struct acpi_video_device *device)
974 {
975         if (acpi_has_method(device->dev->handle, "_ADR"))
976                 device->cap._ADR = 1;
977         if (acpi_has_method(device->dev->handle, "_BCL"))
978                 device->cap._BCL = 1;
979         if (acpi_has_method(device->dev->handle, "_BCM"))
980                 device->cap._BCM = 1;
981         if (acpi_has_method(device->dev->handle, "_BQC")) {
982                 device->cap._BQC = 1;
983         } else if (acpi_has_method(device->dev->handle, "_BCQ")) {
984                 printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
985                 device->cap._BCQ = 1;
986         }
987 
988         if (acpi_has_method(device->dev->handle, "_DDC"))
989                 device->cap._DDC = 1;
990 }
991 
992 /*
993  *  Arg:
994  *      device  : video output device (VGA)
995  *
996  *  Return Value:
997  *      None
998  *
999  *  Find out all required AML methods defined under the video bus device.
1000  */
1001 
1002 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1003 {
1004         if (acpi_has_method(video->device->handle, "_DOS"))
1005                 video->cap._DOS = 1;
1006         if (acpi_has_method(video->device->handle, "_DOD"))
1007                 video->cap._DOD = 1;
1008         if (acpi_has_method(video->device->handle, "_ROM"))
1009                 video->cap._ROM = 1;
1010         if (acpi_has_method(video->device->handle, "_GPD"))
1011                 video->cap._GPD = 1;
1012         if (acpi_has_method(video->device->handle, "_SPD"))
1013                 video->cap._SPD = 1;
1014         if (acpi_has_method(video->device->handle, "_VPO"))
1015                 video->cap._VPO = 1;
1016 }
1017 
1018 /*
1019  * Check whether the video bus device has required AML method to
1020  * support the desired features
1021  */
1022 
1023 static int acpi_video_bus_check(struct acpi_video_bus *video)
1024 {
1025         acpi_status status = -ENOENT;
1026         struct pci_dev *dev;
1027 
1028         if (!video)
1029                 return -EINVAL;
1030 
1031         dev = acpi_get_pci_dev(video->device->handle);
1032         if (!dev)
1033                 return -ENODEV;
1034         pci_dev_put(dev);
1035 
1036         /*
1037          * Since there is no HID, CID and so on for VGA driver, we have
1038          * to check well known required nodes.
1039          */
1040 
1041         /* Does this device support video switching? */
1042         if (video->cap._DOS || video->cap._DOD) {
1043                 if (!video->cap._DOS) {
1044                         printk(KERN_WARNING FW_BUG
1045                                 "ACPI(%s) defines _DOD but not _DOS\n",
1046                                 acpi_device_bid(video->device));
1047                 }
1048                 video->flags.multihead = 1;
1049                 status = 0;
1050         }
1051 
1052         /* Does this device support retrieving a video ROM? */
1053         if (video->cap._ROM) {
1054                 video->flags.rom = 1;
1055                 status = 0;
1056         }
1057 
1058         /* Does this device support configuring which video device to POST? */
1059         if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1060                 video->flags.post = 1;
1061                 status = 0;
1062         }
1063 
1064         return status;
1065 }
1066 
1067 /*
1068  * --------------------------------------------------------------------------
1069  *                               Driver Interface
1070  * --------------------------------------------------------------------------
1071  */
1072 
1073 /* device interface */
1074 static struct acpi_video_device_attrib *
1075 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1076 {
1077         struct acpi_video_enumerated_device *ids;
1078         int i;
1079 
1080         for (i = 0; i < video->attached_count; i++) {
1081                 ids = &video->attached_array[i];
1082                 if ((ids->value.int_val & 0xffff) == device_id)
1083                         return &ids->value.attrib;
1084         }
1085 
1086         return NULL;
1087 }
1088 
1089 static int
1090 acpi_video_get_device_type(struct acpi_video_bus *video,
1091                            unsigned long device_id)
1092 {
1093         struct acpi_video_enumerated_device *ids;
1094         int i;
1095 
1096         for (i = 0; i < video->attached_count; i++) {
1097                 ids = &video->attached_array[i];
1098                 if ((ids->value.int_val & 0xffff) == device_id)
1099                         return ids->value.int_val;
1100         }
1101 
1102         return 0;
1103 }
1104 
1105 static int
1106 acpi_video_bus_get_one_device(struct acpi_device *device,
1107                               struct acpi_video_bus *video)
1108 {
1109         unsigned long long device_id;
1110         int status, device_type;
1111         struct acpi_video_device *data;
1112         struct acpi_video_device_attrib *attribute;
1113 
1114         status =
1115             acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1116         /* Some device omits _ADR, we skip them instead of fail */
1117         if (ACPI_FAILURE(status))
1118                 return 0;
1119 
1120         data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1121         if (!data)
1122                 return -ENOMEM;
1123 
1124         strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1125         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1126         device->driver_data = data;
1127 
1128         data->device_id = device_id;
1129         data->video = video;
1130         data->dev = device;
1131 
1132         attribute = acpi_video_get_device_attr(video, device_id);
1133 
1134         if (attribute && attribute->device_id_scheme) {
1135                 switch (attribute->display_type) {
1136                 case ACPI_VIDEO_DISPLAY_CRT:
1137                         data->flags.crt = 1;
1138                         break;
1139                 case ACPI_VIDEO_DISPLAY_TV:
1140                         data->flags.tvout = 1;
1141                         break;
1142                 case ACPI_VIDEO_DISPLAY_DVI:
1143                         data->flags.dvi = 1;
1144                         break;
1145                 case ACPI_VIDEO_DISPLAY_LCD:
1146                         data->flags.lcd = 1;
1147                         break;
1148                 default:
1149                         data->flags.unknown = 1;
1150                         break;
1151                 }
1152                 if (attribute->bios_can_detect)
1153                         data->flags.bios = 1;
1154         } else {
1155                 /* Check for legacy IDs */
1156                 device_type = acpi_video_get_device_type(video, device_id);
1157                 /* Ignore bits 16 and 18-20 */
1158                 switch (device_type & 0xffe2ffff) {
1159                 case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1160                         data->flags.crt = 1;
1161                         break;
1162                 case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1163                         data->flags.lcd = 1;
1164                         break;
1165                 case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1166                         data->flags.tvout = 1;
1167                         break;
1168                 default:
1169                         data->flags.unknown = 1;
1170                 }
1171         }
1172 
1173         acpi_video_device_bind(video, data);
1174         acpi_video_device_find_cap(data);
1175 
1176         mutex_lock(&video->device_list_lock);
1177         list_add_tail(&data->entry, &video->video_device_list);
1178         mutex_unlock(&video->device_list_lock);
1179 
1180         return status;
1181 }
1182 
1183 /*
1184  *  Arg:
1185  *      video   : video bus device
1186  *
1187  *  Return:
1188  *      none
1189  *
1190  *  Enumerate the video device list of the video bus,
1191  *  bind the ids with the corresponding video devices
1192  *  under the video bus.
1193  */
1194 
1195 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1196 {
1197         struct acpi_video_device *dev;
1198 
1199         mutex_lock(&video->device_list_lock);
1200 
1201         list_for_each_entry(dev, &video->video_device_list, entry)
1202                 acpi_video_device_bind(video, dev);
1203 
1204         mutex_unlock(&video->device_list_lock);
1205 }
1206 
1207 /*
1208  *  Arg:
1209  *      video   : video bus device
1210  *      device  : video output device under the video
1211  *              bus
1212  *
1213  *  Return:
1214  *      none
1215  *
1216  *  Bind the ids with the corresponding video devices
1217  *  under the video bus.
1218  */
1219 
1220 static void
1221 acpi_video_device_bind(struct acpi_video_bus *video,
1222                        struct acpi_video_device *device)
1223 {
1224         struct acpi_video_enumerated_device *ids;
1225         int i;
1226 
1227         for (i = 0; i < video->attached_count; i++) {
1228                 ids = &video->attached_array[i];
1229                 if (device->device_id == (ids->value.int_val & 0xffff)) {
1230                         ids->bind_info = device;
1231                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1232                 }
1233         }
1234 }
1235 
1236 /*
1237  *  Arg:
1238  *      video   : video bus device
1239  *
1240  *  Return:
1241  *      < 0     : error
1242  *
1243  *  Call _DOD to enumerate all devices attached to display adapter
1244  *
1245  */
1246 
1247 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1248 {
1249         int status;
1250         int count;
1251         int i;
1252         struct acpi_video_enumerated_device *active_list;
1253         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1254         union acpi_object *dod = NULL;
1255         union acpi_object *obj;
1256 
1257         status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1258         if (!ACPI_SUCCESS(status)) {
1259                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1260                 return status;
1261         }
1262 
1263         dod = buffer.pointer;
1264         if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1265                 ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1266                 status = -EFAULT;
1267                 goto out;
1268         }
1269 
1270         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1271                           dod->package.count));
1272 
1273         active_list = kcalloc(1 + dod->package.count,
1274                               sizeof(struct acpi_video_enumerated_device),
1275                               GFP_KERNEL);
1276         if (!active_list) {
1277                 status = -ENOMEM;
1278                 goto out;
1279         }
1280 
1281         count = 0;
1282         for (i = 0; i < dod->package.count; i++) {
1283                 obj = &dod->package.elements[i];
1284 
1285                 if (obj->type != ACPI_TYPE_INTEGER) {
1286                         printk(KERN_ERR PREFIX
1287                                 "Invalid _DOD data in element %d\n", i);
1288                         continue;
1289                 }
1290 
1291                 active_list[count].value.int_val = obj->integer.value;
1292                 active_list[count].bind_info = NULL;
1293                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1294                                   (int)obj->integer.value));
1295                 count++;
1296         }
1297 
1298         kfree(video->attached_array);
1299 
1300         video->attached_array = active_list;
1301         video->attached_count = count;
1302 
1303 out:
1304         kfree(buffer.pointer);
1305         return status;
1306 }
1307 
1308 static int
1309 acpi_video_get_next_level(struct acpi_video_device *device,
1310                           u32 level_current, u32 event)
1311 {
1312         int min, max, min_above, max_below, i, l, delta = 255;
1313         max = max_below = 0;
1314         min = min_above = 255;
1315         /* Find closest level to level_current */
1316         for (i = 2; i < device->brightness->count; i++) {
1317                 l = device->brightness->levels[i];
1318                 if (abs(l - level_current) < abs(delta)) {
1319                         delta = l - level_current;
1320                         if (!delta)
1321                                 break;
1322                 }
1323         }
1324         /* Ajust level_current to closest available level */
1325         level_current += delta;
1326         for (i = 2; i < device->brightness->count; i++) {
1327                 l = device->brightness->levels[i];
1328                 if (l < min)
1329                         min = l;
1330                 if (l > max)
1331                         max = l;
1332                 if (l < min_above && l > level_current)
1333                         min_above = l;
1334                 if (l > max_below && l < level_current)
1335                         max_below = l;
1336         }
1337 
1338         switch (event) {
1339         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1340                 return (level_current < max) ? min_above : min;
1341         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1342                 return (level_current < max) ? min_above : max;
1343         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1344                 return (level_current > min) ? max_below : min;
1345         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1346         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1347                 return 0;
1348         default:
1349                 return level_current;
1350         }
1351 }
1352 
1353 static int
1354 acpi_video_switch_brightness(struct acpi_video_device *device, int event)
1355 {
1356         unsigned long long level_current, level_next;
1357         int result = -EINVAL;
1358 
1359         /* no warning message if acpi_backlight=vendor or a quirk is used */
1360         if (!acpi_video_verify_backlight_support())
1361                 return 0;
1362 
1363         if (!device->brightness)
1364                 goto out;
1365 
1366         result = acpi_video_device_lcd_get_level_current(device,
1367                                                          &level_current,
1368                                                          false);
1369         if (result)
1370                 goto out;
1371 
1372         level_next = acpi_video_get_next_level(device, level_current, event);
1373 
1374         result = acpi_video_device_lcd_set_level(device, level_next);
1375 
1376         if (!result)
1377                 backlight_force_update(device->backlight,
1378                                        BACKLIGHT_UPDATE_HOTKEY);
1379 
1380 out:
1381         if (result)
1382                 printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1383 
1384         return result;
1385 }
1386 
1387 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1388                         void **edid)
1389 {
1390         struct acpi_video_bus *video;
1391         struct acpi_video_device *video_device;
1392         union acpi_object *buffer = NULL;
1393         acpi_status status;
1394         int i, length;
1395 
1396         if (!device || !acpi_driver_data(device))
1397                 return -EINVAL;
1398 
1399         video = acpi_driver_data(device);
1400 
1401         for (i = 0; i < video->attached_count; i++) {
1402                 video_device = video->attached_array[i].bind_info;
1403                 length = 256;
1404 
1405                 if (!video_device)
1406                         continue;
1407 
1408                 if (!video_device->cap._DDC)
1409                         continue;
1410 
1411                 if (type) {
1412                         switch (type) {
1413                         case ACPI_VIDEO_DISPLAY_CRT:
1414                                 if (!video_device->flags.crt)
1415                                         continue;
1416                                 break;
1417                         case ACPI_VIDEO_DISPLAY_TV:
1418                                 if (!video_device->flags.tvout)
1419                                         continue;
1420                                 break;
1421                         case ACPI_VIDEO_DISPLAY_DVI:
1422                                 if (!video_device->flags.dvi)
1423                                         continue;
1424                                 break;
1425                         case ACPI_VIDEO_DISPLAY_LCD:
1426                                 if (!video_device->flags.lcd)
1427                                         continue;
1428                                 break;
1429                         }
1430                 } else if (video_device->device_id != device_id) {
1431                         continue;
1432                 }
1433 
1434                 status = acpi_video_device_EDID(video_device, &buffer, length);
1435 
1436                 if (ACPI_FAILURE(status) || !buffer ||
1437                     buffer->type != ACPI_TYPE_BUFFER) {
1438                         length = 128;
1439                         status = acpi_video_device_EDID(video_device, &buffer,
1440                                                         length);
1441                         if (ACPI_FAILURE(status) || !buffer ||
1442                             buffer->type != ACPI_TYPE_BUFFER) {
1443                                 continue;
1444                         }
1445                 }
1446 
1447                 *edid = buffer->buffer.pointer;
1448                 return length;
1449         }
1450 
1451         return -ENODEV;
1452 }
1453 EXPORT_SYMBOL(acpi_video_get_edid);
1454 
1455 static int
1456 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1457                            struct acpi_device *device)
1458 {
1459         int status = 0;
1460         struct acpi_device *dev;
1461 
1462         /*
1463          * There are systems where video module known to work fine regardless
1464          * of broken _DOD and ignoring returned value here doesn't cause
1465          * any issues later.
1466          */
1467         acpi_video_device_enumerate(video);
1468 
1469         list_for_each_entry(dev, &device->children, node) {
1470 
1471                 status = acpi_video_bus_get_one_device(dev, video);
1472                 if (status) {
1473                         dev_err(&dev->dev, "Can't attach device\n");
1474                         break;
1475                 }
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 acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1553 {
1554         struct acpi_video_device *video_device = data;
1555         struct acpi_device *device = NULL;
1556         struct acpi_video_bus *bus;
1557         struct input_dev *input;
1558         int keycode = 0;
1559 
1560         if (!video_device)
1561                 return;
1562 
1563         device = video_device->dev;
1564         bus = video_device->video;
1565         input = bus->input;
1566 
1567         switch (event) {
1568         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:        /* Cycle brightness */
1569                 if (brightness_switch_enabled)
1570                         acpi_video_switch_brightness(video_device, event);
1571                 keycode = KEY_BRIGHTNESS_CYCLE;
1572                 break;
1573         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
1574                 if (brightness_switch_enabled)
1575                         acpi_video_switch_brightness(video_device, event);
1576                 keycode = KEY_BRIGHTNESSUP;
1577                 break;
1578         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
1579                 if (brightness_switch_enabled)
1580                         acpi_video_switch_brightness(video_device, event);
1581                 keycode = KEY_BRIGHTNESSDOWN;
1582                 break;
1583         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
1584                 if (brightness_switch_enabled)
1585                         acpi_video_switch_brightness(video_device, event);
1586                 keycode = KEY_BRIGHTNESS_ZERO;
1587                 break;
1588         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
1589                 if (brightness_switch_enabled)
1590                         acpi_video_switch_brightness(video_device, event);
1591                 keycode = KEY_DISPLAY_OFF;
1592                 break;
1593         default:
1594                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1595                                   "Unsupported event [0x%x]\n", event));
1596                 break;
1597         }
1598 
1599         acpi_notifier_call_chain(device, event, 0);
1600 
1601         if (keycode) {
1602                 input_report_key(input, keycode, 1);
1603                 input_sync(input);
1604                 input_report_key(input, keycode, 0);
1605                 input_sync(input);
1606         }
1607 
1608         return;
1609 }
1610 
1611 static int acpi_video_resume(struct notifier_block *nb,
1612                                 unsigned long val, void *ign)
1613 {
1614         struct acpi_video_bus *video;
1615         struct acpi_video_device *video_device;
1616         int i;
1617 
1618         switch (val) {
1619         case PM_HIBERNATION_PREPARE:
1620         case PM_SUSPEND_PREPARE:
1621         case PM_RESTORE_PREPARE:
1622                 return NOTIFY_DONE;
1623         }
1624 
1625         video = container_of(nb, struct acpi_video_bus, pm_nb);
1626 
1627         dev_info(&video->device->dev, "Restoring backlight state\n");
1628 
1629         for (i = 0; i < video->attached_count; i++) {
1630                 video_device = video->attached_array[i].bind_info;
1631                 if (video_device && video_device->backlight)
1632                         acpi_video_set_brightness(video_device->backlight);
1633         }
1634 
1635         return NOTIFY_OK;
1636 }
1637 
1638 static acpi_status
1639 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1640                         void **return_value)
1641 {
1642         struct acpi_device *device = context;
1643         struct acpi_device *sibling;
1644         int result;
1645 
1646         if (handle == device->handle)
1647                 return AE_CTRL_TERMINATE;
1648 
1649         result = acpi_bus_get_device(handle, &sibling);
1650         if (result)
1651                 return AE_OK;
1652 
1653         if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1654                         return AE_ALREADY_EXISTS;
1655 
1656         return AE_OK;
1657 }
1658 
1659 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1660 {
1661         if (acpi_video_verify_backlight_support()) {
1662                 struct backlight_properties props;
1663                 struct pci_dev *pdev;
1664                 acpi_handle acpi_parent;
1665                 struct device *parent = NULL;
1666                 int result;
1667                 static int count;
1668                 char *name;
1669 
1670                 result = acpi_video_init_brightness(device);
1671                 if (result)
1672                         return;
1673                 name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1674                 if (!name)
1675                         return;
1676                 count++;
1677 
1678                 acpi_get_parent(device->dev->handle, &acpi_parent);
1679 
1680                 pdev = acpi_get_pci_dev(acpi_parent);
1681                 if (pdev) {
1682                         parent = &pdev->dev;
1683                         pci_dev_put(pdev);
1684                 }
1685 
1686                 memset(&props, 0, sizeof(struct backlight_properties));
1687                 props.type = BACKLIGHT_FIRMWARE;
1688                 props.max_brightness = device->brightness->count - 3;
1689                 device->backlight = backlight_device_register(name,
1690                                                               parent,
1691                                                               device,
1692                                                               &acpi_backlight_ops,
1693                                                               &props);
1694                 kfree(name);
1695                 if (IS_ERR(device->backlight))
1696                         return;
1697 
1698                 /*
1699                  * Save current brightness level in case we have to restore it
1700                  * before acpi_video_device_lcd_set_level() is called next time.
1701                  */
1702                 device->backlight->props.brightness =
1703                                 acpi_video_get_brightness(device->backlight);
1704 
1705                 device->cooling_dev = thermal_cooling_device_register("LCD",
1706                                         device->dev, &video_cooling_ops);
1707                 if (IS_ERR(device->cooling_dev)) {
1708                         /*
1709                          * Set cooling_dev to NULL so we don't crash trying to
1710                          * free it.
1711                          * Also, why the hell we are returning early and
1712                          * not attempt to register video output if cooling
1713                          * device registration failed?
1714                          * -- dtor
1715                          */
1716                         device->cooling_dev = NULL;
1717                         return;
1718                 }
1719 
1720                 dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1721                          device->cooling_dev->id);
1722                 result = sysfs_create_link(&device->dev->dev.kobj,
1723                                 &device->cooling_dev->device.kobj,
1724                                 "thermal_cooling");
1725                 if (result)
1726                         printk(KERN_ERR PREFIX "Create sysfs link\n");
1727                 result = sysfs_create_link(&device->cooling_dev->device.kobj,
1728                                 &device->dev->dev.kobj, "device");
1729                 if (result)
1730                         printk(KERN_ERR PREFIX "Create sysfs link\n");
1731         }
1732 }
1733 
1734 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1735 {
1736         struct acpi_video_device *dev;
1737 
1738         mutex_lock(&video->device_list_lock);
1739         list_for_each_entry(dev, &video->video_device_list, entry)
1740                 acpi_video_dev_register_backlight(dev);
1741         mutex_unlock(&video->device_list_lock);
1742 
1743         video->pm_nb.notifier_call = acpi_video_resume;
1744         video->pm_nb.priority = 0;
1745         return register_pm_notifier(&video->pm_nb);
1746 }
1747 
1748 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1749 {
1750         if (device->backlight) {
1751                 backlight_device_unregister(device->backlight);
1752                 device->backlight = NULL;
1753         }
1754         if (device->brightness) {
1755                 kfree(device->brightness->levels);
1756                 kfree(device->brightness);
1757                 device->brightness = NULL;
1758         }
1759         if (device->cooling_dev) {
1760                 sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1761                 sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1762                 thermal_cooling_device_unregister(device->cooling_dev);
1763                 device->cooling_dev = NULL;
1764         }
1765 }
1766 
1767 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1768 {
1769         struct acpi_video_device *dev;
1770         int error = unregister_pm_notifier(&video->pm_nb);
1771 
1772         mutex_lock(&video->device_list_lock);
1773         list_for_each_entry(dev, &video->video_device_list, entry)
1774                 acpi_video_dev_unregister_backlight(dev);
1775         mutex_unlock(&video->device_list_lock);
1776 
1777         return error;
1778 }
1779 
1780 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1781 {
1782         acpi_status status;
1783         struct acpi_device *adev = device->dev;
1784 
1785         status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1786                                              acpi_video_device_notify, device);
1787         if (ACPI_FAILURE(status))
1788                 dev_err(&adev->dev, "Error installing notify handler\n");
1789         else
1790                 device->flags.notify = 1;
1791 }
1792 
1793 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1794 {
1795         struct input_dev *input;
1796         struct acpi_video_device *dev;
1797         int error;
1798 
1799         video->input = input = input_allocate_device();
1800         if (!input) {
1801                 error = -ENOMEM;
1802                 goto out;
1803         }
1804 
1805         error = acpi_video_bus_start_devices(video);
1806         if (error)
1807                 goto err_free_input;
1808 
1809         snprintf(video->phys, sizeof(video->phys),
1810                         "%s/video/input0", acpi_device_hid(video->device));
1811 
1812         input->name = acpi_device_name(video->device);
1813         input->phys = video->phys;
1814         input->id.bustype = BUS_HOST;
1815         input->id.product = 0x06;
1816         input->dev.parent = &video->device->dev;
1817         input->evbit[0] = BIT(EV_KEY);
1818         set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1819         set_bit(KEY_VIDEO_NEXT, input->keybit);
1820         set_bit(KEY_VIDEO_PREV, input->keybit);
1821         set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1822         set_bit(KEY_BRIGHTNESSUP, input->keybit);
1823         set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1824         set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1825         set_bit(KEY_DISPLAY_OFF, input->keybit);
1826 
1827         error = input_register_device(input);
1828         if (error)
1829                 goto err_stop_dev;
1830 
1831         mutex_lock(&video->device_list_lock);
1832         list_for_each_entry(dev, &video->video_device_list, entry)
1833                 acpi_video_dev_add_notify_handler(dev);
1834         mutex_unlock(&video->device_list_lock);
1835 
1836         return 0;
1837 
1838 err_stop_dev:
1839         acpi_video_bus_stop_devices(video);
1840 err_free_input:
1841         input_free_device(input);
1842         video->input = NULL;
1843 out:
1844         return error;
1845 }
1846 
1847 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1848 {
1849         if (dev->flags.notify) {
1850                 acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1851                                            acpi_video_device_notify);
1852                 dev->flags.notify = 0;
1853         }
1854 }
1855 
1856 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1857 {
1858         struct acpi_video_device *dev;
1859 
1860         mutex_lock(&video->device_list_lock);
1861         list_for_each_entry(dev, &video->video_device_list, entry)
1862                 acpi_video_dev_remove_notify_handler(dev);
1863         mutex_unlock(&video->device_list_lock);
1864 
1865         acpi_video_bus_stop_devices(video);
1866         input_unregister_device(video->input);
1867         video->input = NULL;
1868 }
1869 
1870 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1871 {
1872         struct acpi_video_device *dev, *next;
1873 
1874         mutex_lock(&video->device_list_lock);
1875         list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1876                 list_del(&dev->entry);
1877                 kfree(dev);
1878         }
1879         mutex_unlock(&video->device_list_lock);
1880 
1881         return 0;
1882 }
1883 
1884 static int instance;
1885 
1886 static int acpi_video_bus_add(struct acpi_device *device)
1887 {
1888         struct acpi_video_bus *video;
1889         int error;
1890         acpi_status status;
1891 
1892         status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1893                                 device->parent->handle, 1,
1894                                 acpi_video_bus_match, NULL,
1895                                 device, NULL);
1896         if (status == AE_ALREADY_EXISTS) {
1897                 printk(KERN_WARNING FW_BUG
1898                         "Duplicate ACPI video bus devices for the"
1899                         " same VGA controller, please try module "
1900                         "parameter \"video.allow_duplicates=1\""
1901                         "if the current driver doesn't work.\n");
1902                 if (!allow_duplicates)
1903                         return -ENODEV;
1904         }
1905 
1906         video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1907         if (!video)
1908                 return -ENOMEM;
1909 
1910         /* a hack to fix the duplicate name "VID" problem on T61 */
1911         if (!strcmp(device->pnp.bus_id, "VID")) {
1912                 if (instance)
1913                         device->pnp.bus_id[3] = '' + instance;
1914                 instance++;
1915         }
1916         /* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
1917         if (!strcmp(device->pnp.bus_id, "VGA")) {
1918                 if (instance)
1919                         device->pnp.bus_id[3] = '' + instance;
1920                 instance++;
1921         }
1922 
1923         video->device = device;
1924         strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
1925         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1926         device->driver_data = video;
1927 
1928         acpi_video_bus_find_cap(video);
1929         error = acpi_video_bus_check(video);
1930         if (error)
1931                 goto err_free_video;
1932 
1933         mutex_init(&video->device_list_lock);
1934         INIT_LIST_HEAD(&video->video_device_list);
1935 
1936         error = acpi_video_bus_get_devices(video, device);
1937         if (error)
1938                 goto err_put_video;
1939 
1940         printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
1941                ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
1942                video->flags.multihead ? "yes" : "no",
1943                video->flags.rom ? "yes" : "no",
1944                video->flags.post ? "yes" : "no");
1945         mutex_lock(&video_list_lock);
1946         list_add_tail(&video->entry, &video_bus_head);
1947         mutex_unlock(&video_list_lock);
1948 
1949         acpi_video_bus_register_backlight(video);
1950         acpi_video_bus_add_notify_handler(video);
1951 
1952         return 0;
1953 
1954 err_put_video:
1955         acpi_video_bus_put_devices(video);
1956         kfree(video->attached_array);
1957 err_free_video:
1958         kfree(video);
1959         device->driver_data = NULL;
1960 
1961         return error;
1962 }
1963 
1964 static int acpi_video_bus_remove(struct acpi_device *device)
1965 {
1966         struct acpi_video_bus *video = NULL;
1967 
1968 
1969         if (!device || !acpi_driver_data(device))
1970                 return -EINVAL;
1971 
1972         video = acpi_driver_data(device);
1973 
1974         acpi_video_bus_remove_notify_handler(video);
1975         acpi_video_bus_unregister_backlight(video);
1976         acpi_video_bus_put_devices(video);
1977 
1978         mutex_lock(&video_list_lock);
1979         list_del(&video->entry);
1980         mutex_unlock(&video_list_lock);
1981 
1982         kfree(video->attached_array);
1983         kfree(video);
1984 
1985         return 0;
1986 }
1987 
1988 static int __init is_i740(struct pci_dev *dev)
1989 {
1990         if (dev->device == 0x00D1)
1991                 return 1;
1992         if (dev->device == 0x7000)
1993                 return 1;
1994         return 0;
1995 }
1996 
1997 static int __init intel_opregion_present(void)
1998 {
1999         int opregion = 0;
2000         struct pci_dev *dev = NULL;
2001         u32 address;
2002 
2003         for_each_pci_dev(dev) {
2004                 if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2005                         continue;
2006                 if (dev->vendor != PCI_VENDOR_ID_INTEL)
2007                         continue;
2008                 /* We don't want to poke around undefined i740 registers */
2009                 if (is_i740(dev))
2010                         continue;
2011                 pci_read_config_dword(dev, 0xfc, &address);
2012                 if (!address)
2013                         continue;
2014                 opregion = 1;
2015         }
2016         return opregion;
2017 }
2018 
2019 int acpi_video_register(void)
2020 {
2021         int result = 0;
2022         if (register_count) {
2023                 /*
2024                  * if the function of acpi_video_register is already called,
2025                  * don't register the acpi_vide_bus again and return no error.
2026                  */
2027                 return 0;
2028         }
2029 
2030         mutex_init(&video_list_lock);
2031         INIT_LIST_HEAD(&video_bus_head);
2032 
2033         result = acpi_bus_register_driver(&acpi_video_bus);
2034         if (result < 0)
2035                 return -ENODEV;
2036 
2037         /*
2038          * When the acpi_video_bus is loaded successfully, increase
2039          * the counter reference.
2040          */
2041         register_count = 1;
2042 
2043         return 0;
2044 }
2045 EXPORT_SYMBOL(acpi_video_register);
2046 
2047 void acpi_video_unregister(void)
2048 {
2049         if (!register_count) {
2050                 /*
2051                  * If the acpi video bus is already unloaded, don't
2052                  * unload it again and return directly.
2053                  */
2054                 return;
2055         }
2056         acpi_bus_unregister_driver(&acpi_video_bus);
2057 
2058         register_count = 0;
2059 
2060         return;
2061 }
2062 EXPORT_SYMBOL(acpi_video_unregister);
2063 
2064 /*
2065  * This is kind of nasty. Hardware using Intel chipsets may require
2066  * the video opregion code to be run first in order to initialise
2067  * state before any ACPI video calls are made. To handle this we defer
2068  * registration of the video class until the opregion code has run.
2069  */
2070 
2071 static int __init acpi_video_init(void)
2072 {
2073         dmi_check_system(video_dmi_table);
2074 
2075         if (intel_opregion_present())
2076                 return 0;
2077 
2078         return acpi_video_register();
2079 }
2080 
2081 static void __exit acpi_video_exit(void)
2082 {
2083         acpi_video_unregister();
2084 
2085         return;
2086 }
2087 
2088 module_init(acpi_video_init);
2089 module_exit(acpi_video_exit);
2090 

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