xref: /openbmc/linux/drivers/acpi/acpi_video.c (revision 3805e6a1)
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  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
21  */
22 
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/types.h>
27 #include <linux/list.h>
28 #include <linux/mutex.h>
29 #include <linux/input.h>
30 #include <linux/backlight.h>
31 #include <linux/thermal.h>
32 #include <linux/sort.h>
33 #include <linux/pci.h>
34 #include <linux/pci_ids.h>
35 #include <linux/slab.h>
36 #include <linux/dmi.h>
37 #include <linux/suspend.h>
38 #include <linux/acpi.h>
39 #include <acpi/video.h>
40 #include <asm/uaccess.h>
41 
42 #define PREFIX "ACPI: "
43 
44 #define ACPI_VIDEO_BUS_NAME		"Video Bus"
45 #define ACPI_VIDEO_DEVICE_NAME		"Video Device"
46 #define ACPI_VIDEO_NOTIFY_SWITCH	0x80
47 #define ACPI_VIDEO_NOTIFY_PROBE		0x81
48 #define ACPI_VIDEO_NOTIFY_CYCLE		0x82
49 #define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT	0x83
50 #define ACPI_VIDEO_NOTIFY_PREV_OUTPUT	0x84
51 
52 #define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS	0x85
53 #define	ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS	0x86
54 #define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS	0x87
55 #define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS	0x88
56 #define ACPI_VIDEO_NOTIFY_DISPLAY_OFF		0x89
57 
58 #define MAX_NAME_LEN	20
59 
60 #define _COMPONENT		ACPI_VIDEO_COMPONENT
61 ACPI_MODULE_NAME("video");
62 
63 MODULE_AUTHOR("Bruno Ducrot");
64 MODULE_DESCRIPTION("ACPI Video Driver");
65 MODULE_LICENSE("GPL");
66 
67 static bool brightness_switch_enabled = 1;
68 module_param(brightness_switch_enabled, bool, 0644);
69 
70 /*
71  * By default, we don't allow duplicate ACPI video bus devices
72  * under the same VGA controller
73  */
74 static bool allow_duplicates;
75 module_param(allow_duplicates, bool, 0644);
76 
77 static int disable_backlight_sysfs_if = -1;
78 module_param(disable_backlight_sysfs_if, int, 0444);
79 
80 #define REPORT_OUTPUT_KEY_EVENTS		0x01
81 #define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
82 static int report_key_events = -1;
83 module_param(report_key_events, int, 0644);
84 MODULE_PARM_DESC(report_key_events,
85 	"0: none, 1: output changes, 2: brightness changes, 3: all");
86 
87 static bool device_id_scheme = false;
88 module_param(device_id_scheme, bool, 0444);
89 
90 static bool only_lcd = false;
91 module_param(only_lcd, bool, 0444);
92 
93 static int register_count;
94 static DEFINE_MUTEX(register_count_mutex);
95 static DEFINE_MUTEX(video_list_lock);
96 static LIST_HEAD(video_bus_head);
97 static int acpi_video_bus_add(struct acpi_device *device);
98 static int acpi_video_bus_remove(struct acpi_device *device);
99 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
100 void acpi_video_detect_exit(void);
101 
102 static const struct acpi_device_id video_device_ids[] = {
103 	{ACPI_VIDEO_HID, 0},
104 	{"", 0},
105 };
106 MODULE_DEVICE_TABLE(acpi, video_device_ids);
107 
108 static struct acpi_driver acpi_video_bus = {
109 	.name = "video",
110 	.class = ACPI_VIDEO_CLASS,
111 	.ids = video_device_ids,
112 	.ops = {
113 		.add = acpi_video_bus_add,
114 		.remove = acpi_video_bus_remove,
115 		.notify = acpi_video_bus_notify,
116 		},
117 };
118 
119 struct acpi_video_bus_flags {
120 	u8 multihead:1;		/* can switch video heads */
121 	u8 rom:1;		/* can retrieve a video rom */
122 	u8 post:1;		/* can configure the head to */
123 	u8 reserved:5;
124 };
125 
126 struct acpi_video_bus_cap {
127 	u8 _DOS:1;		/* Enable/Disable output switching */
128 	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
129 	u8 _ROM:1;		/* Get ROM Data */
130 	u8 _GPD:1;		/* Get POST Device */
131 	u8 _SPD:1;		/* Set POST Device */
132 	u8 _VPO:1;		/* Video POST Options */
133 	u8 reserved:2;
134 };
135 
136 struct acpi_video_device_attrib {
137 	u32 display_index:4;	/* A zero-based instance of the Display */
138 	u32 display_port_attachment:4;	/* This field differentiates the display type */
139 	u32 display_type:4;	/* Describe the specific type in use */
140 	u32 vendor_specific:4;	/* Chipset Vendor Specific */
141 	u32 bios_can_detect:1;	/* BIOS can detect the device */
142 	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
143 				   the VGA device. */
144 	u32 pipe_id:3;		/* For VGA multiple-head devices. */
145 	u32 reserved:10;	/* Must be 0 */
146 	u32 device_id_scheme:1;	/* Device ID Scheme */
147 };
148 
149 struct acpi_video_enumerated_device {
150 	union {
151 		u32 int_val;
152 		struct acpi_video_device_attrib attrib;
153 	} value;
154 	struct acpi_video_device *bind_info;
155 };
156 
157 struct acpi_video_bus {
158 	struct acpi_device *device;
159 	bool backlight_registered;
160 	u8 dos_setting;
161 	struct acpi_video_enumerated_device *attached_array;
162 	u8 attached_count;
163 	u8 child_count;
164 	struct acpi_video_bus_cap cap;
165 	struct acpi_video_bus_flags flags;
166 	struct list_head video_device_list;
167 	struct mutex device_list_lock;	/* protects video_device_list */
168 	struct list_head entry;
169 	struct input_dev *input;
170 	char phys[32];	/* for input device */
171 	struct notifier_block pm_nb;
172 };
173 
174 struct acpi_video_device_flags {
175 	u8 crt:1;
176 	u8 lcd:1;
177 	u8 tvout:1;
178 	u8 dvi:1;
179 	u8 bios:1;
180 	u8 unknown:1;
181 	u8 notify:1;
182 	u8 reserved:1;
183 };
184 
185 struct acpi_video_device_cap {
186 	u8 _ADR:1;		/* Return the unique ID */
187 	u8 _BCL:1;		/* Query list of brightness control levels supported */
188 	u8 _BCM:1;		/* Set the brightness level */
189 	u8 _BQC:1;		/* Get current brightness level */
190 	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
191 	u8 _DDC:1;		/* Return the EDID for this device */
192 };
193 
194 struct acpi_video_device {
195 	unsigned long device_id;
196 	struct acpi_video_device_flags flags;
197 	struct acpi_video_device_cap cap;
198 	struct list_head entry;
199 	struct delayed_work switch_brightness_work;
200 	int switch_brightness_event;
201 	struct acpi_video_bus *video;
202 	struct acpi_device *dev;
203 	struct acpi_video_device_brightness *brightness;
204 	struct backlight_device *backlight;
205 	struct thermal_cooling_device *cooling_dev;
206 };
207 
208 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
209 static void acpi_video_device_rebind(struct acpi_video_bus *video);
210 static void acpi_video_device_bind(struct acpi_video_bus *video,
211 				   struct acpi_video_device *device);
212 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
213 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
214 			int level);
215 static int acpi_video_device_lcd_get_level_current(
216 			struct acpi_video_device *device,
217 			unsigned long long *level, bool raw);
218 static int acpi_video_get_next_level(struct acpi_video_device *device,
219 				     u32 level_current, u32 event);
220 static void acpi_video_switch_brightness(struct work_struct *work);
221 
222 /* backlight device sysfs support */
223 static int acpi_video_get_brightness(struct backlight_device *bd)
224 {
225 	unsigned long long cur_level;
226 	int i;
227 	struct acpi_video_device *vd = bl_get_data(bd);
228 
229 	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
230 		return -EINVAL;
231 	for (i = 2; i < vd->brightness->count; i++) {
232 		if (vd->brightness->levels[i] == cur_level)
233 			/*
234 			 * The first two entries are special - see page 575
235 			 * of the ACPI spec 3.0
236 			 */
237 			return i - 2;
238 	}
239 	return 0;
240 }
241 
242 static int acpi_video_set_brightness(struct backlight_device *bd)
243 {
244 	int request_level = bd->props.brightness + 2;
245 	struct acpi_video_device *vd = bl_get_data(bd);
246 
247 	cancel_delayed_work(&vd->switch_brightness_work);
248 	return acpi_video_device_lcd_set_level(vd,
249 				vd->brightness->levels[request_level]);
250 }
251 
252 static const struct backlight_ops acpi_backlight_ops = {
253 	.get_brightness = acpi_video_get_brightness,
254 	.update_status  = acpi_video_set_brightness,
255 };
256 
257 /* thermal cooling device callbacks */
258 static int video_get_max_state(struct thermal_cooling_device *cooling_dev, unsigned
259 			       long *state)
260 {
261 	struct acpi_device *device = cooling_dev->devdata;
262 	struct acpi_video_device *video = acpi_driver_data(device);
263 
264 	*state = video->brightness->count - 3;
265 	return 0;
266 }
267 
268 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsigned
269 			       long *state)
270 {
271 	struct acpi_device *device = cooling_dev->devdata;
272 	struct acpi_video_device *video = acpi_driver_data(device);
273 	unsigned long long level;
274 	int offset;
275 
276 	if (acpi_video_device_lcd_get_level_current(video, &level, false))
277 		return -EINVAL;
278 	for (offset = 2; offset < video->brightness->count; offset++)
279 		if (level == video->brightness->levels[offset]) {
280 			*state = video->brightness->count - offset - 1;
281 			return 0;
282 		}
283 
284 	return -EINVAL;
285 }
286 
287 static int
288 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
289 {
290 	struct acpi_device *device = cooling_dev->devdata;
291 	struct acpi_video_device *video = acpi_driver_data(device);
292 	int level;
293 
294 	if (state >= video->brightness->count - 2)
295 		return -EINVAL;
296 
297 	state = video->brightness->count - state;
298 	level = video->brightness->levels[state - 1];
299 	return acpi_video_device_lcd_set_level(video, level);
300 }
301 
302 static const struct thermal_cooling_device_ops video_cooling_ops = {
303 	.get_max_state = video_get_max_state,
304 	.get_cur_state = video_get_cur_state,
305 	.set_cur_state = video_set_cur_state,
306 };
307 
308 /*
309  * --------------------------------------------------------------------------
310  *                             Video Management
311  * --------------------------------------------------------------------------
312  */
313 
314 static int
315 acpi_video_device_lcd_query_levels(acpi_handle handle,
316 				   union acpi_object **levels)
317 {
318 	int status;
319 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
320 	union acpi_object *obj;
321 
322 
323 	*levels = NULL;
324 
325 	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
326 	if (!ACPI_SUCCESS(status))
327 		return status;
328 	obj = (union acpi_object *)buffer.pointer;
329 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
330 		printk(KERN_ERR PREFIX "Invalid _BCL data\n");
331 		status = -EFAULT;
332 		goto err;
333 	}
334 
335 	*levels = obj;
336 
337 	return 0;
338 
339 err:
340 	kfree(buffer.pointer);
341 
342 	return status;
343 }
344 
345 static int
346 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
347 {
348 	int status;
349 	int state;
350 
351 	status = acpi_execute_simple_method(device->dev->handle,
352 					    "_BCM", level);
353 	if (ACPI_FAILURE(status)) {
354 		ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
355 		return -EIO;
356 	}
357 
358 	device->brightness->curr = level;
359 	for (state = 2; state < device->brightness->count; state++)
360 		if (level == device->brightness->levels[state]) {
361 			if (device->backlight)
362 				device->backlight->props.brightness = state - 2;
363 			return 0;
364 		}
365 
366 	ACPI_ERROR((AE_INFO, "Current brightness invalid"));
367 	return -EINVAL;
368 }
369 
370 /*
371  * For some buggy _BQC methods, we need to add a constant value to
372  * the _BQC return value to get the actual current brightness level
373  */
374 
375 static int bqc_offset_aml_bug_workaround;
376 static int video_set_bqc_offset(const struct dmi_system_id *d)
377 {
378 	bqc_offset_aml_bug_workaround = 9;
379 	return 0;
380 }
381 
382 static int video_disable_backlight_sysfs_if(
383 	const struct dmi_system_id *d)
384 {
385 	if (disable_backlight_sysfs_if == -1)
386 		disable_backlight_sysfs_if = 1;
387 	return 0;
388 }
389 
390 static int video_set_device_id_scheme(const struct dmi_system_id *d)
391 {
392 	device_id_scheme = true;
393 	return 0;
394 }
395 
396 static int video_enable_only_lcd(const struct dmi_system_id *d)
397 {
398 	only_lcd = true;
399 	return 0;
400 }
401 
402 static int video_set_report_key_events(const struct dmi_system_id *id)
403 {
404 	if (report_key_events == -1)
405 		report_key_events = (uintptr_t)id->driver_data;
406 	return 0;
407 }
408 
409 static struct dmi_system_id video_dmi_table[] = {
410 	/*
411 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
412 	 */
413 	{
414 	 .callback = video_set_bqc_offset,
415 	 .ident = "Acer Aspire 5720",
416 	 .matches = {
417 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
418 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
419 		},
420 	},
421 	{
422 	 .callback = video_set_bqc_offset,
423 	 .ident = "Acer Aspire 5710Z",
424 	 .matches = {
425 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
426 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
427 		},
428 	},
429 	{
430 	 .callback = video_set_bqc_offset,
431 	 .ident = "eMachines E510",
432 	 .matches = {
433 		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
434 		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
435 		},
436 	},
437 	{
438 	 .callback = video_set_bqc_offset,
439 	 .ident = "Acer Aspire 5315",
440 	 .matches = {
441 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
442 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
443 		},
444 	},
445 	{
446 	 .callback = video_set_bqc_offset,
447 	 .ident = "Acer Aspire 7720",
448 	 .matches = {
449 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
450 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
451 		},
452 	},
453 
454 	/*
455 	 * Some machines have a broken acpi-video interface for brightness
456 	 * control, but still need an acpi_video_device_lcd_set_level() call
457 	 * on resume to turn the backlight power on.  We Enable backlight
458 	 * control on these systems, but do not register a backlight sysfs
459 	 * as brightness control does not work.
460 	 */
461 	{
462 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
463 	 .callback = video_disable_backlight_sysfs_if,
464 	 .ident = "Toshiba Portege R700",
465 	 .matches = {
466 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
467 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
468 		},
469 	},
470 	{
471 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
472 	 .callback = video_disable_backlight_sysfs_if,
473 	 .ident = "Toshiba Portege R830",
474 	 .matches = {
475 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
476 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
477 		},
478 	},
479 	{
480 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
481 	 .callback = video_disable_backlight_sysfs_if,
482 	 .ident = "Toshiba Satellite R830",
483 	 .matches = {
484 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
485 		DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
486 		},
487 	},
488 	/*
489 	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
490 	 * but the IDs actually follow the Device ID Scheme.
491 	 */
492 	{
493 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
494 	 .callback = video_set_device_id_scheme,
495 	 .ident = "ESPRIMO Mobile M9410",
496 	 .matches = {
497 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
498 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
499 		},
500 	},
501 	/*
502 	 * Some machines have multiple video output devices, but only the one
503 	 * that is the type of LCD can do the backlight control so we should not
504 	 * register backlight interface for other video output devices.
505 	 */
506 	{
507 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
508 	 .callback = video_enable_only_lcd,
509 	 .ident = "ESPRIMO Mobile M9410",
510 	 .matches = {
511 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
512 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
513 		},
514 	},
515 	/*
516 	 * Some machines report wrong key events on the acpi-bus, suppress
517 	 * key event reporting on these.  Note this is only intended to work
518 	 * around events which are plain wrong. In some cases we get double
519 	 * events, in this case acpi-video is considered the canonical source
520 	 * and the events from the other source should be filtered. E.g.
521 	 * by calling acpi_video_handles_brightness_key_presses() from the
522 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
523 	 */
524 	{
525 	 .callback = video_set_report_key_events,
526 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
527 	 .ident = "Dell Vostro V131",
528 	 .matches = {
529 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
530 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
531 		},
532 	},
533 	{}
534 };
535 
536 static unsigned long long
537 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
538 			      unsigned long long bqc_value)
539 {
540 	unsigned long long level;
541 
542 	if (device->brightness->flags._BQC_use_index) {
543 		/*
544 		 * _BQC returns an index that doesn't account for
545 		 * the first 2 items with special meaning, so we need
546 		 * to compensate for that by offsetting ourselves
547 		 */
548 		if (device->brightness->flags._BCL_reversed)
549 			bqc_value = device->brightness->count - 3 - bqc_value;
550 
551 		level = device->brightness->levels[bqc_value + 2];
552 	} else {
553 		level = bqc_value;
554 	}
555 
556 	level += bqc_offset_aml_bug_workaround;
557 
558 	return level;
559 }
560 
561 static int
562 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
563 					unsigned long long *level, bool raw)
564 {
565 	acpi_status status = AE_OK;
566 	int i;
567 
568 	if (device->cap._BQC || device->cap._BCQ) {
569 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
570 
571 		status = acpi_evaluate_integer(device->dev->handle, buf,
572 						NULL, level);
573 		if (ACPI_SUCCESS(status)) {
574 			if (raw) {
575 				/*
576 				 * Caller has indicated he wants the raw
577 				 * value returned by _BQC, so don't furtherly
578 				 * mess with the value.
579 				 */
580 				return 0;
581 			}
582 
583 			*level = acpi_video_bqc_value_to_level(device, *level);
584 
585 			for (i = 2; i < device->brightness->count; i++)
586 				if (device->brightness->levels[i] == *level) {
587 					device->brightness->curr = *level;
588 					return 0;
589 				}
590 			/*
591 			 * BQC returned an invalid level.
592 			 * Stop using it.
593 			 */
594 			ACPI_WARNING((AE_INFO,
595 				      "%s returned an invalid level",
596 				      buf));
597 			device->cap._BQC = device->cap._BCQ = 0;
598 		} else {
599 			/*
600 			 * Fixme:
601 			 * should we return an error or ignore this failure?
602 			 * dev->brightness->curr is a cached value which stores
603 			 * the correct current backlight level in most cases.
604 			 * ACPI video backlight still works w/ buggy _BQC.
605 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
606 			 */
607 			ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
608 			device->cap._BQC = device->cap._BCQ = 0;
609 		}
610 	}
611 
612 	*level = device->brightness->curr;
613 	return 0;
614 }
615 
616 static int
617 acpi_video_device_EDID(struct acpi_video_device *device,
618 		       union acpi_object **edid, ssize_t length)
619 {
620 	int status;
621 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
622 	union acpi_object *obj;
623 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
624 	struct acpi_object_list args = { 1, &arg0 };
625 
626 
627 	*edid = NULL;
628 
629 	if (!device)
630 		return -ENODEV;
631 	if (length == 128)
632 		arg0.integer.value = 1;
633 	else if (length == 256)
634 		arg0.integer.value = 2;
635 	else
636 		return -EINVAL;
637 
638 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
639 	if (ACPI_FAILURE(status))
640 		return -ENODEV;
641 
642 	obj = buffer.pointer;
643 
644 	if (obj && obj->type == ACPI_TYPE_BUFFER)
645 		*edid = obj;
646 	else {
647 		printk(KERN_ERR PREFIX "Invalid _DDC data\n");
648 		status = -EFAULT;
649 		kfree(obj);
650 	}
651 
652 	return status;
653 }
654 
655 /* bus */
656 
657 /*
658  *  Arg:
659  *	video		: video bus device pointer
660  *	bios_flag	:
661  *		0.	The system BIOS should NOT automatically switch(toggle)
662  *			the active display output.
663  *		1.	The system BIOS should automatically switch (toggle) the
664  *			active display output. No switch event.
665  *		2.	The _DGS value should be locked.
666  *		3.	The system BIOS should not automatically switch (toggle) the
667  *			active display output, but instead generate the display switch
668  *			event notify code.
669  *	lcd_flag	:
670  *		0.	The system BIOS should automatically control the brightness level
671  *			of the LCD when the power changes from AC to DC
672  *		1.	The system BIOS should NOT automatically control the brightness
673  *			level of the LCD when the power changes from AC to DC.
674  *  Return Value:
675  *		-EINVAL	wrong arg.
676  */
677 
678 static int
679 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
680 {
681 	acpi_status status;
682 
683 	if (!video->cap._DOS)
684 		return 0;
685 
686 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
687 		return -EINVAL;
688 	video->dos_setting = (lcd_flag << 2) | bios_flag;
689 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
690 					    (lcd_flag << 2) | bios_flag);
691 	if (ACPI_FAILURE(status))
692 		return -EIO;
693 
694 	return 0;
695 }
696 
697 /*
698  * Simple comparison function used to sort backlight levels.
699  */
700 
701 static int
702 acpi_video_cmp_level(const void *a, const void *b)
703 {
704 	return *(int *)a - *(int *)b;
705 }
706 
707 /*
708  * Decides if _BQC/_BCQ for this system is usable
709  *
710  * We do this by changing the level first and then read out the current
711  * brightness level, if the value does not match, find out if it is using
712  * index. If not, clear the _BQC/_BCQ capability.
713  */
714 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
715 				int max_level, int current_level)
716 {
717 	struct acpi_video_device_brightness *br = device->brightness;
718 	int result;
719 	unsigned long long level;
720 	int test_level;
721 
722 	/* don't mess with existing known broken systems */
723 	if (bqc_offset_aml_bug_workaround)
724 		return 0;
725 
726 	/*
727 	 * Some systems always report current brightness level as maximum
728 	 * through _BQC, we need to test another value for them.
729 	 */
730 	test_level = current_level == max_level ? br->levels[3] : max_level;
731 
732 	result = acpi_video_device_lcd_set_level(device, test_level);
733 	if (result)
734 		return result;
735 
736 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
737 	if (result)
738 		return result;
739 
740 	if (level != test_level) {
741 		/* buggy _BQC found, need to find out if it uses index */
742 		if (level < br->count) {
743 			if (br->flags._BCL_reversed)
744 				level = br->count - 3 - level;
745 			if (br->levels[level + 2] == test_level)
746 				br->flags._BQC_use_index = 1;
747 		}
748 
749 		if (!br->flags._BQC_use_index)
750 			device->cap._BQC = device->cap._BCQ = 0;
751 	}
752 
753 	return 0;
754 }
755 
756 int acpi_video_get_levels(struct acpi_device *device,
757 			  struct acpi_video_device_brightness **dev_br)
758 {
759 	union acpi_object *obj = NULL;
760 	int i, max_level = 0, count = 0, level_ac_battery = 0;
761 	union acpi_object *o;
762 	struct acpi_video_device_brightness *br = NULL;
763 	int result = 0;
764 	u32 value;
765 
766 	if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device->handle,
767 								&obj))) {
768 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
769 						"LCD brightness level\n"));
770 		result = -ENODEV;
771 		goto out;
772 	}
773 
774 	if (obj->package.count < 2) {
775 		result = -EINVAL;
776 		goto out;
777 	}
778 
779 	br = kzalloc(sizeof(*br), GFP_KERNEL);
780 	if (!br) {
781 		printk(KERN_ERR "can't allocate memory\n");
782 		result = -ENOMEM;
783 		goto out;
784 	}
785 
786 	br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
787 				GFP_KERNEL);
788 	if (!br->levels) {
789 		result = -ENOMEM;
790 		goto out_free;
791 	}
792 
793 	for (i = 0; i < obj->package.count; i++) {
794 		o = (union acpi_object *)&obj->package.elements[i];
795 		if (o->type != ACPI_TYPE_INTEGER) {
796 			printk(KERN_ERR PREFIX "Invalid data\n");
797 			continue;
798 		}
799 		value = (u32) o->integer.value;
800 		/* Skip duplicate entries */
801 		if (count > 2 && br->levels[count - 1] == value)
802 			continue;
803 
804 		br->levels[count] = value;
805 
806 		if (br->levels[count] > max_level)
807 			max_level = br->levels[count];
808 		count++;
809 	}
810 
811 	/*
812 	 * some buggy BIOS don't export the levels
813 	 * when machine is on AC/Battery in _BCL package.
814 	 * In this case, the first two elements in _BCL packages
815 	 * are also supported brightness levels that OS should take care of.
816 	 */
817 	for (i = 2; i < count; i++) {
818 		if (br->levels[i] == br->levels[0])
819 			level_ac_battery++;
820 		if (br->levels[i] == br->levels[1])
821 			level_ac_battery++;
822 	}
823 
824 	if (level_ac_battery < 2) {
825 		level_ac_battery = 2 - level_ac_battery;
826 		br->flags._BCL_no_ac_battery_levels = 1;
827 		for (i = (count - 1 + level_ac_battery); i >= 2; i--)
828 			br->levels[i] = br->levels[i - level_ac_battery];
829 		count += level_ac_battery;
830 	} else if (level_ac_battery > 2)
831 		ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
832 
833 	/* Check if the _BCL package is in a reversed order */
834 	if (max_level == br->levels[2]) {
835 		br->flags._BCL_reversed = 1;
836 		sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
837 			acpi_video_cmp_level, NULL);
838 	} else if (max_level != br->levels[count - 1])
839 		ACPI_ERROR((AE_INFO,
840 			    "Found unordered _BCL package"));
841 
842 	br->count = count;
843 	*dev_br = br;
844 
845 out:
846 	kfree(obj);
847 	return result;
848 out_free:
849 	kfree(br);
850 	goto out;
851 }
852 EXPORT_SYMBOL(acpi_video_get_levels);
853 
854 /*
855  *  Arg:
856  *	device	: video output device (LCD, CRT, ..)
857  *
858  *  Return Value:
859  *	Maximum brightness level
860  *
861  *  Allocate and initialize device->brightness.
862  */
863 
864 static int
865 acpi_video_init_brightness(struct acpi_video_device *device)
866 {
867 	int i, max_level = 0;
868 	unsigned long long level, level_old;
869 	struct acpi_video_device_brightness *br = NULL;
870 	int result = -EINVAL;
871 
872 	result = acpi_video_get_levels(device->dev, &br);
873 	if (result)
874 		return result;
875 	device->brightness = br;
876 
877 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
878 	br->curr = level = max_level;
879 
880 	if (!device->cap._BQC)
881 		goto set_level;
882 
883 	result = acpi_video_device_lcd_get_level_current(device,
884 							 &level_old, true);
885 	if (result)
886 		goto out_free_levels;
887 
888 	result = acpi_video_bqc_quirk(device, max_level, level_old);
889 	if (result)
890 		goto out_free_levels;
891 	/*
892 	 * cap._BQC may get cleared due to _BQC is found to be broken
893 	 * in acpi_video_bqc_quirk, so check again here.
894 	 */
895 	if (!device->cap._BQC)
896 		goto set_level;
897 
898 	level = acpi_video_bqc_value_to_level(device, level_old);
899 	/*
900 	 * On some buggy laptops, _BQC returns an uninitialized
901 	 * value when invoked for the first time, i.e.
902 	 * level_old is invalid (no matter whether it's a level
903 	 * or an index). Set the backlight to max_level in this case.
904 	 */
905 	for (i = 2; i < br->count; i++)
906 		if (level == br->levels[i])
907 			break;
908 	if (i == br->count || !level)
909 		level = max_level;
910 
911 set_level:
912 	result = acpi_video_device_lcd_set_level(device, level);
913 	if (result)
914 		goto out_free_levels;
915 
916 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
917 			  "found %d brightness levels\n", br->count - 2));
918 	return 0;
919 
920 out_free_levels:
921 	kfree(br->levels);
922 	kfree(br);
923 	device->brightness = NULL;
924 	return result;
925 }
926 
927 /*
928  *  Arg:
929  *	device	: video output device (LCD, CRT, ..)
930  *
931  *  Return Value:
932  *	None
933  *
934  *  Find out all required AML methods defined under the output
935  *  device.
936  */
937 
938 static void acpi_video_device_find_cap(struct acpi_video_device *device)
939 {
940 	if (acpi_has_method(device->dev->handle, "_ADR"))
941 		device->cap._ADR = 1;
942 	if (acpi_has_method(device->dev->handle, "_BCL"))
943 		device->cap._BCL = 1;
944 	if (acpi_has_method(device->dev->handle, "_BCM"))
945 		device->cap._BCM = 1;
946 	if (acpi_has_method(device->dev->handle, "_BQC")) {
947 		device->cap._BQC = 1;
948 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
949 		printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
950 		device->cap._BCQ = 1;
951 	}
952 
953 	if (acpi_has_method(device->dev->handle, "_DDC"))
954 		device->cap._DDC = 1;
955 }
956 
957 /*
958  *  Arg:
959  *	device	: video output device (VGA)
960  *
961  *  Return Value:
962  *	None
963  *
964  *  Find out all required AML methods defined under the video bus device.
965  */
966 
967 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
968 {
969 	if (acpi_has_method(video->device->handle, "_DOS"))
970 		video->cap._DOS = 1;
971 	if (acpi_has_method(video->device->handle, "_DOD"))
972 		video->cap._DOD = 1;
973 	if (acpi_has_method(video->device->handle, "_ROM"))
974 		video->cap._ROM = 1;
975 	if (acpi_has_method(video->device->handle, "_GPD"))
976 		video->cap._GPD = 1;
977 	if (acpi_has_method(video->device->handle, "_SPD"))
978 		video->cap._SPD = 1;
979 	if (acpi_has_method(video->device->handle, "_VPO"))
980 		video->cap._VPO = 1;
981 }
982 
983 /*
984  * Check whether the video bus device has required AML method to
985  * support the desired features
986  */
987 
988 static int acpi_video_bus_check(struct acpi_video_bus *video)
989 {
990 	acpi_status status = -ENOENT;
991 	struct pci_dev *dev;
992 
993 	if (!video)
994 		return -EINVAL;
995 
996 	dev = acpi_get_pci_dev(video->device->handle);
997 	if (!dev)
998 		return -ENODEV;
999 	pci_dev_put(dev);
1000 
1001 	/*
1002 	 * Since there is no HID, CID and so on for VGA driver, we have
1003 	 * to check well known required nodes.
1004 	 */
1005 
1006 	/* Does this device support video switching? */
1007 	if (video->cap._DOS || video->cap._DOD) {
1008 		if (!video->cap._DOS) {
1009 			printk(KERN_WARNING FW_BUG
1010 				"ACPI(%s) defines _DOD but not _DOS\n",
1011 				acpi_device_bid(video->device));
1012 		}
1013 		video->flags.multihead = 1;
1014 		status = 0;
1015 	}
1016 
1017 	/* Does this device support retrieving a video ROM? */
1018 	if (video->cap._ROM) {
1019 		video->flags.rom = 1;
1020 		status = 0;
1021 	}
1022 
1023 	/* Does this device support configuring which video device to POST? */
1024 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1025 		video->flags.post = 1;
1026 		status = 0;
1027 	}
1028 
1029 	return status;
1030 }
1031 
1032 /*
1033  * --------------------------------------------------------------------------
1034  *                               Driver Interface
1035  * --------------------------------------------------------------------------
1036  */
1037 
1038 /* device interface */
1039 static struct acpi_video_device_attrib *
1040 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1041 {
1042 	struct acpi_video_enumerated_device *ids;
1043 	int i;
1044 
1045 	for (i = 0; i < video->attached_count; i++) {
1046 		ids = &video->attached_array[i];
1047 		if ((ids->value.int_val & 0xffff) == device_id)
1048 			return &ids->value.attrib;
1049 	}
1050 
1051 	return NULL;
1052 }
1053 
1054 static int
1055 acpi_video_get_device_type(struct acpi_video_bus *video,
1056 			   unsigned long device_id)
1057 {
1058 	struct acpi_video_enumerated_device *ids;
1059 	int i;
1060 
1061 	for (i = 0; i < video->attached_count; i++) {
1062 		ids = &video->attached_array[i];
1063 		if ((ids->value.int_val & 0xffff) == device_id)
1064 			return ids->value.int_val;
1065 	}
1066 
1067 	return 0;
1068 }
1069 
1070 static int
1071 acpi_video_bus_get_one_device(struct acpi_device *device,
1072 			      struct acpi_video_bus *video)
1073 {
1074 	unsigned long long device_id;
1075 	int status, device_type;
1076 	struct acpi_video_device *data;
1077 	struct acpi_video_device_attrib *attribute;
1078 
1079 	status =
1080 	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1081 	/* Some device omits _ADR, we skip them instead of fail */
1082 	if (ACPI_FAILURE(status))
1083 		return 0;
1084 
1085 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1086 	if (!data)
1087 		return -ENOMEM;
1088 
1089 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1090 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1091 	device->driver_data = data;
1092 
1093 	data->device_id = device_id;
1094 	data->video = video;
1095 	data->dev = device;
1096 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1097 			  acpi_video_switch_brightness);
1098 
1099 	attribute = acpi_video_get_device_attr(video, device_id);
1100 
1101 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1102 		switch (attribute->display_type) {
1103 		case ACPI_VIDEO_DISPLAY_CRT:
1104 			data->flags.crt = 1;
1105 			break;
1106 		case ACPI_VIDEO_DISPLAY_TV:
1107 			data->flags.tvout = 1;
1108 			break;
1109 		case ACPI_VIDEO_DISPLAY_DVI:
1110 			data->flags.dvi = 1;
1111 			break;
1112 		case ACPI_VIDEO_DISPLAY_LCD:
1113 			data->flags.lcd = 1;
1114 			break;
1115 		default:
1116 			data->flags.unknown = 1;
1117 			break;
1118 		}
1119 		if (attribute->bios_can_detect)
1120 			data->flags.bios = 1;
1121 	} else {
1122 		/* Check for legacy IDs */
1123 		device_type = acpi_video_get_device_type(video, device_id);
1124 		/* Ignore bits 16 and 18-20 */
1125 		switch (device_type & 0xffe2ffff) {
1126 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1127 			data->flags.crt = 1;
1128 			break;
1129 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1130 			data->flags.lcd = 1;
1131 			break;
1132 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1133 			data->flags.tvout = 1;
1134 			break;
1135 		default:
1136 			data->flags.unknown = 1;
1137 		}
1138 	}
1139 
1140 	acpi_video_device_bind(video, data);
1141 	acpi_video_device_find_cap(data);
1142 
1143 	mutex_lock(&video->device_list_lock);
1144 	list_add_tail(&data->entry, &video->video_device_list);
1145 	mutex_unlock(&video->device_list_lock);
1146 
1147 	return status;
1148 }
1149 
1150 /*
1151  *  Arg:
1152  *	video	: video bus device
1153  *
1154  *  Return:
1155  *	none
1156  *
1157  *  Enumerate the video device list of the video bus,
1158  *  bind the ids with the corresponding video devices
1159  *  under the video bus.
1160  */
1161 
1162 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1163 {
1164 	struct acpi_video_device *dev;
1165 
1166 	mutex_lock(&video->device_list_lock);
1167 
1168 	list_for_each_entry(dev, &video->video_device_list, entry)
1169 		acpi_video_device_bind(video, dev);
1170 
1171 	mutex_unlock(&video->device_list_lock);
1172 }
1173 
1174 /*
1175  *  Arg:
1176  *	video	: video bus device
1177  *	device	: video output device under the video
1178  *		bus
1179  *
1180  *  Return:
1181  *	none
1182  *
1183  *  Bind the ids with the corresponding video devices
1184  *  under the video bus.
1185  */
1186 
1187 static void
1188 acpi_video_device_bind(struct acpi_video_bus *video,
1189 		       struct acpi_video_device *device)
1190 {
1191 	struct acpi_video_enumerated_device *ids;
1192 	int i;
1193 
1194 	for (i = 0; i < video->attached_count; i++) {
1195 		ids = &video->attached_array[i];
1196 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1197 			ids->bind_info = device;
1198 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1199 		}
1200 	}
1201 }
1202 
1203 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1204 {
1205 	struct acpi_video_bus *video = device->video;
1206 	int i;
1207 
1208 	/*
1209 	 * If we have a broken _DOD or we have more than 8 output devices
1210 	 * under the graphics controller node that we can't proper deal with
1211 	 * in the operation region code currently, no need to test.
1212 	 */
1213 	if (!video->attached_count || video->child_count > 8)
1214 		return true;
1215 
1216 	for (i = 0; i < video->attached_count; i++) {
1217 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1218 		    (device->device_id & 0xfff))
1219 			return true;
1220 	}
1221 
1222 	return false;
1223 }
1224 
1225 /*
1226  *  Arg:
1227  *	video	: video bus device
1228  *
1229  *  Return:
1230  *	< 0	: error
1231  *
1232  *  Call _DOD to enumerate all devices attached to display adapter
1233  *
1234  */
1235 
1236 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1237 {
1238 	int status;
1239 	int count;
1240 	int i;
1241 	struct acpi_video_enumerated_device *active_list;
1242 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1243 	union acpi_object *dod = NULL;
1244 	union acpi_object *obj;
1245 
1246 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1247 	if (!ACPI_SUCCESS(status)) {
1248 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1249 		return status;
1250 	}
1251 
1252 	dod = buffer.pointer;
1253 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1254 		ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1255 		status = -EFAULT;
1256 		goto out;
1257 	}
1258 
1259 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1260 			  dod->package.count));
1261 
1262 	active_list = kcalloc(1 + dod->package.count,
1263 			      sizeof(struct acpi_video_enumerated_device),
1264 			      GFP_KERNEL);
1265 	if (!active_list) {
1266 		status = -ENOMEM;
1267 		goto out;
1268 	}
1269 
1270 	count = 0;
1271 	for (i = 0; i < dod->package.count; i++) {
1272 		obj = &dod->package.elements[i];
1273 
1274 		if (obj->type != ACPI_TYPE_INTEGER) {
1275 			printk(KERN_ERR PREFIX
1276 				"Invalid _DOD data in element %d\n", i);
1277 			continue;
1278 		}
1279 
1280 		active_list[count].value.int_val = obj->integer.value;
1281 		active_list[count].bind_info = NULL;
1282 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1283 				  (int)obj->integer.value));
1284 		count++;
1285 	}
1286 
1287 	kfree(video->attached_array);
1288 
1289 	video->attached_array = active_list;
1290 	video->attached_count = count;
1291 
1292 out:
1293 	kfree(buffer.pointer);
1294 	return status;
1295 }
1296 
1297 static int
1298 acpi_video_get_next_level(struct acpi_video_device *device,
1299 			  u32 level_current, u32 event)
1300 {
1301 	int min, max, min_above, max_below, i, l, delta = 255;
1302 	max = max_below = 0;
1303 	min = min_above = 255;
1304 	/* Find closest level to level_current */
1305 	for (i = 2; i < device->brightness->count; i++) {
1306 		l = device->brightness->levels[i];
1307 		if (abs(l - level_current) < abs(delta)) {
1308 			delta = l - level_current;
1309 			if (!delta)
1310 				break;
1311 		}
1312 	}
1313 	/* Ajust level_current to closest available level */
1314 	level_current += delta;
1315 	for (i = 2; i < device->brightness->count; i++) {
1316 		l = device->brightness->levels[i];
1317 		if (l < min)
1318 			min = l;
1319 		if (l > max)
1320 			max = l;
1321 		if (l < min_above && l > level_current)
1322 			min_above = l;
1323 		if (l > max_below && l < level_current)
1324 			max_below = l;
1325 	}
1326 
1327 	switch (event) {
1328 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1329 		return (level_current < max) ? min_above : min;
1330 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1331 		return (level_current < max) ? min_above : max;
1332 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1333 		return (level_current > min) ? max_below : min;
1334 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1335 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1336 		return 0;
1337 	default:
1338 		return level_current;
1339 	}
1340 }
1341 
1342 static void
1343 acpi_video_switch_brightness(struct work_struct *work)
1344 {
1345 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1346 			     struct acpi_video_device, switch_brightness_work);
1347 	unsigned long long level_current, level_next;
1348 	int event = device->switch_brightness_event;
1349 	int result = -EINVAL;
1350 
1351 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1352 	if (!device->backlight)
1353 		return;
1354 
1355 	if (!device->brightness)
1356 		goto out;
1357 
1358 	result = acpi_video_device_lcd_get_level_current(device,
1359 							 &level_current,
1360 							 false);
1361 	if (result)
1362 		goto out;
1363 
1364 	level_next = acpi_video_get_next_level(device, level_current, event);
1365 
1366 	result = acpi_video_device_lcd_set_level(device, level_next);
1367 
1368 	if (!result)
1369 		backlight_force_update(device->backlight,
1370 				       BACKLIGHT_UPDATE_HOTKEY);
1371 
1372 out:
1373 	if (result)
1374 		printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1375 }
1376 
1377 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1378 			void **edid)
1379 {
1380 	struct acpi_video_bus *video;
1381 	struct acpi_video_device *video_device;
1382 	union acpi_object *buffer = NULL;
1383 	acpi_status status;
1384 	int i, length;
1385 
1386 	if (!device || !acpi_driver_data(device))
1387 		return -EINVAL;
1388 
1389 	video = acpi_driver_data(device);
1390 
1391 	for (i = 0; i < video->attached_count; i++) {
1392 		video_device = video->attached_array[i].bind_info;
1393 		length = 256;
1394 
1395 		if (!video_device)
1396 			continue;
1397 
1398 		if (!video_device->cap._DDC)
1399 			continue;
1400 
1401 		if (type) {
1402 			switch (type) {
1403 			case ACPI_VIDEO_DISPLAY_CRT:
1404 				if (!video_device->flags.crt)
1405 					continue;
1406 				break;
1407 			case ACPI_VIDEO_DISPLAY_TV:
1408 				if (!video_device->flags.tvout)
1409 					continue;
1410 				break;
1411 			case ACPI_VIDEO_DISPLAY_DVI:
1412 				if (!video_device->flags.dvi)
1413 					continue;
1414 				break;
1415 			case ACPI_VIDEO_DISPLAY_LCD:
1416 				if (!video_device->flags.lcd)
1417 					continue;
1418 				break;
1419 			}
1420 		} else if (video_device->device_id != device_id) {
1421 			continue;
1422 		}
1423 
1424 		status = acpi_video_device_EDID(video_device, &buffer, length);
1425 
1426 		if (ACPI_FAILURE(status) || !buffer ||
1427 		    buffer->type != ACPI_TYPE_BUFFER) {
1428 			length = 128;
1429 			status = acpi_video_device_EDID(video_device, &buffer,
1430 							length);
1431 			if (ACPI_FAILURE(status) || !buffer ||
1432 			    buffer->type != ACPI_TYPE_BUFFER) {
1433 				continue;
1434 			}
1435 		}
1436 
1437 		*edid = buffer->buffer.pointer;
1438 		return length;
1439 	}
1440 
1441 	return -ENODEV;
1442 }
1443 EXPORT_SYMBOL(acpi_video_get_edid);
1444 
1445 static int
1446 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1447 			   struct acpi_device *device)
1448 {
1449 	int status = 0;
1450 	struct acpi_device *dev;
1451 
1452 	/*
1453 	 * There are systems where video module known to work fine regardless
1454 	 * of broken _DOD and ignoring returned value here doesn't cause
1455 	 * any issues later.
1456 	 */
1457 	acpi_video_device_enumerate(video);
1458 
1459 	list_for_each_entry(dev, &device->children, node) {
1460 
1461 		status = acpi_video_bus_get_one_device(dev, video);
1462 		if (status) {
1463 			dev_err(&dev->dev, "Can't attach device\n");
1464 			break;
1465 		}
1466 		video->child_count++;
1467 	}
1468 	return status;
1469 }
1470 
1471 /* acpi_video interface */
1472 
1473 /*
1474  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1475  * preform any automatic brightness change on receiving a notification.
1476  */
1477 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1478 {
1479 	return acpi_video_bus_DOS(video, 0,
1480 				  acpi_osi_is_win8() ? 1 : 0);
1481 }
1482 
1483 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1484 {
1485 	return acpi_video_bus_DOS(video, 0,
1486 				  acpi_osi_is_win8() ? 0 : 1);
1487 }
1488 
1489 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1490 {
1491 	struct acpi_video_bus *video = acpi_driver_data(device);
1492 	struct input_dev *input;
1493 	int keycode = 0;
1494 
1495 	if (!video || !video->input)
1496 		return;
1497 
1498 	input = video->input;
1499 
1500 	switch (event) {
1501 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1502 					 * most likely via hotkey. */
1503 		keycode = KEY_SWITCHVIDEOMODE;
1504 		break;
1505 
1506 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1507 					 * connector. */
1508 		acpi_video_device_enumerate(video);
1509 		acpi_video_device_rebind(video);
1510 		keycode = KEY_SWITCHVIDEOMODE;
1511 		break;
1512 
1513 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1514 		keycode = KEY_SWITCHVIDEOMODE;
1515 		break;
1516 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1517 		keycode = KEY_VIDEO_NEXT;
1518 		break;
1519 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1520 		keycode = KEY_VIDEO_PREV;
1521 		break;
1522 
1523 	default:
1524 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1525 				  "Unsupported event [0x%x]\n", event));
1526 		break;
1527 	}
1528 
1529 	if (acpi_notifier_call_chain(device, event, 0))
1530 		/* Something vetoed the keypress. */
1531 		keycode = 0;
1532 
1533 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1534 		input_report_key(input, keycode, 1);
1535 		input_sync(input);
1536 		input_report_key(input, keycode, 0);
1537 		input_sync(input);
1538 	}
1539 
1540 	return;
1541 }
1542 
1543 static void brightness_switch_event(struct acpi_video_device *video_device,
1544 				    u32 event)
1545 {
1546 	if (!brightness_switch_enabled)
1547 		return;
1548 
1549 	video_device->switch_brightness_event = event;
1550 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1551 }
1552 
1553 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1554 {
1555 	struct acpi_video_device *video_device = data;
1556 	struct acpi_device *device = NULL;
1557 	struct acpi_video_bus *bus;
1558 	struct input_dev *input;
1559 	int keycode = 0;
1560 
1561 	if (!video_device)
1562 		return;
1563 
1564 	device = video_device->dev;
1565 	bus = video_device->video;
1566 	input = bus->input;
1567 
1568 	switch (event) {
1569 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1570 		brightness_switch_event(video_device, event);
1571 		keycode = KEY_BRIGHTNESS_CYCLE;
1572 		break;
1573 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1574 		brightness_switch_event(video_device, event);
1575 		keycode = KEY_BRIGHTNESSUP;
1576 		break;
1577 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1578 		brightness_switch_event(video_device, event);
1579 		keycode = KEY_BRIGHTNESSDOWN;
1580 		break;
1581 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1582 		brightness_switch_event(video_device, event);
1583 		keycode = KEY_BRIGHTNESS_ZERO;
1584 		break;
1585 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1586 		brightness_switch_event(video_device, event);
1587 		keycode = KEY_DISPLAY_OFF;
1588 		break;
1589 	default:
1590 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1591 				  "Unsupported event [0x%x]\n", event));
1592 		break;
1593 	}
1594 
1595 	acpi_notifier_call_chain(device, event, 0);
1596 
1597 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1598 		input_report_key(input, keycode, 1);
1599 		input_sync(input);
1600 		input_report_key(input, keycode, 0);
1601 		input_sync(input);
1602 	}
1603 
1604 	return;
1605 }
1606 
1607 static int acpi_video_resume(struct notifier_block *nb,
1608 				unsigned long val, void *ign)
1609 {
1610 	struct acpi_video_bus *video;
1611 	struct acpi_video_device *video_device;
1612 	int i;
1613 
1614 	switch (val) {
1615 	case PM_HIBERNATION_PREPARE:
1616 	case PM_SUSPEND_PREPARE:
1617 	case PM_RESTORE_PREPARE:
1618 		return NOTIFY_DONE;
1619 	}
1620 
1621 	video = container_of(nb, struct acpi_video_bus, pm_nb);
1622 
1623 	dev_info(&video->device->dev, "Restoring backlight state\n");
1624 
1625 	for (i = 0; i < video->attached_count; i++) {
1626 		video_device = video->attached_array[i].bind_info;
1627 		if (video_device && video_device->brightness)
1628 			acpi_video_device_lcd_set_level(video_device,
1629 					video_device->brightness->curr);
1630 	}
1631 
1632 	return NOTIFY_OK;
1633 }
1634 
1635 static acpi_status
1636 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1637 			void **return_value)
1638 {
1639 	struct acpi_device *device = context;
1640 	struct acpi_device *sibling;
1641 	int result;
1642 
1643 	if (handle == device->handle)
1644 		return AE_CTRL_TERMINATE;
1645 
1646 	result = acpi_bus_get_device(handle, &sibling);
1647 	if (result)
1648 		return AE_OK;
1649 
1650 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1651 			return AE_ALREADY_EXISTS;
1652 
1653 	return AE_OK;
1654 }
1655 
1656 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1657 {
1658 	struct backlight_properties props;
1659 	struct pci_dev *pdev;
1660 	acpi_handle acpi_parent;
1661 	struct device *parent = NULL;
1662 	int result;
1663 	static int count;
1664 	char *name;
1665 
1666 	result = acpi_video_init_brightness(device);
1667 	if (result)
1668 		return;
1669 
1670 	if (disable_backlight_sysfs_if > 0)
1671 		return;
1672 
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 		device->backlight = NULL;
1697 		return;
1698 	}
1699 
1700 	/*
1701 	 * Save current brightness level in case we have to restore it
1702 	 * before acpi_video_device_lcd_set_level() is called next time.
1703 	 */
1704 	device->backlight->props.brightness =
1705 			acpi_video_get_brightness(device->backlight);
1706 
1707 	device->cooling_dev = thermal_cooling_device_register("LCD",
1708 				device->dev, &video_cooling_ops);
1709 	if (IS_ERR(device->cooling_dev)) {
1710 		/*
1711 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1712 		 * Also, why the hell we are returning early and not attempt to
1713 		 * register video output if cooling 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 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1734 {
1735 	struct acpi_video_device *dev;
1736 	union acpi_object *levels;
1737 
1738 	mutex_lock(&video->device_list_lock);
1739 	list_for_each_entry(dev, &video->video_device_list, entry) {
1740 		if (!acpi_video_device_lcd_query_levels(dev, &levels))
1741 			kfree(levels);
1742 	}
1743 	mutex_unlock(&video->device_list_lock);
1744 }
1745 
1746 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1747 {
1748 	/*
1749 	 * Do not create backlight device for video output
1750 	 * device that is not in the enumerated list.
1751 	 */
1752 	if (!acpi_video_device_in_dod(dev)) {
1753 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1754 		return false;
1755 	}
1756 
1757 	if (only_lcd)
1758 		return dev->flags.lcd;
1759 	return true;
1760 }
1761 
1762 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1763 {
1764 	struct acpi_video_device *dev;
1765 
1766 	if (video->backlight_registered)
1767 		return 0;
1768 
1769 	acpi_video_run_bcl_for_osi(video);
1770 
1771 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1772 		return 0;
1773 
1774 	mutex_lock(&video->device_list_lock);
1775 	list_for_each_entry(dev, &video->video_device_list, entry) {
1776 		if (acpi_video_should_register_backlight(dev))
1777 			acpi_video_dev_register_backlight(dev);
1778 	}
1779 	mutex_unlock(&video->device_list_lock);
1780 
1781 	video->backlight_registered = true;
1782 
1783 	video->pm_nb.notifier_call = acpi_video_resume;
1784 	video->pm_nb.priority = 0;
1785 	return register_pm_notifier(&video->pm_nb);
1786 }
1787 
1788 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1789 {
1790 	if (device->backlight) {
1791 		backlight_device_unregister(device->backlight);
1792 		device->backlight = NULL;
1793 	}
1794 	if (device->brightness) {
1795 		kfree(device->brightness->levels);
1796 		kfree(device->brightness);
1797 		device->brightness = NULL;
1798 	}
1799 	if (device->cooling_dev) {
1800 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1801 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1802 		thermal_cooling_device_unregister(device->cooling_dev);
1803 		device->cooling_dev = NULL;
1804 	}
1805 }
1806 
1807 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1808 {
1809 	struct acpi_video_device *dev;
1810 	int error;
1811 
1812 	if (!video->backlight_registered)
1813 		return 0;
1814 
1815 	error = unregister_pm_notifier(&video->pm_nb);
1816 
1817 	mutex_lock(&video->device_list_lock);
1818 	list_for_each_entry(dev, &video->video_device_list, entry)
1819 		acpi_video_dev_unregister_backlight(dev);
1820 	mutex_unlock(&video->device_list_lock);
1821 
1822 	video->backlight_registered = false;
1823 
1824 	return error;
1825 }
1826 
1827 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1828 {
1829 	acpi_status status;
1830 	struct acpi_device *adev = device->dev;
1831 
1832 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1833 					     acpi_video_device_notify, device);
1834 	if (ACPI_FAILURE(status))
1835 		dev_err(&adev->dev, "Error installing notify handler\n");
1836 	else
1837 		device->flags.notify = 1;
1838 }
1839 
1840 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1841 {
1842 	struct input_dev *input;
1843 	struct acpi_video_device *dev;
1844 	int error;
1845 
1846 	video->input = input = input_allocate_device();
1847 	if (!input) {
1848 		error = -ENOMEM;
1849 		goto out;
1850 	}
1851 
1852 	error = acpi_video_bus_start_devices(video);
1853 	if (error)
1854 		goto err_free_input;
1855 
1856 	snprintf(video->phys, sizeof(video->phys),
1857 			"%s/video/input0", acpi_device_hid(video->device));
1858 
1859 	input->name = acpi_device_name(video->device);
1860 	input->phys = video->phys;
1861 	input->id.bustype = BUS_HOST;
1862 	input->id.product = 0x06;
1863 	input->dev.parent = &video->device->dev;
1864 	input->evbit[0] = BIT(EV_KEY);
1865 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1866 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1867 	set_bit(KEY_VIDEO_PREV, input->keybit);
1868 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1869 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1870 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1871 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1872 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1873 
1874 	error = input_register_device(input);
1875 	if (error)
1876 		goto err_stop_dev;
1877 
1878 	mutex_lock(&video->device_list_lock);
1879 	list_for_each_entry(dev, &video->video_device_list, entry)
1880 		acpi_video_dev_add_notify_handler(dev);
1881 	mutex_unlock(&video->device_list_lock);
1882 
1883 	return 0;
1884 
1885 err_stop_dev:
1886 	acpi_video_bus_stop_devices(video);
1887 err_free_input:
1888 	input_free_device(input);
1889 	video->input = NULL;
1890 out:
1891 	return error;
1892 }
1893 
1894 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1895 {
1896 	if (dev->flags.notify) {
1897 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1898 					   acpi_video_device_notify);
1899 		dev->flags.notify = 0;
1900 	}
1901 }
1902 
1903 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1904 {
1905 	struct acpi_video_device *dev;
1906 
1907 	mutex_lock(&video->device_list_lock);
1908 	list_for_each_entry(dev, &video->video_device_list, entry)
1909 		acpi_video_dev_remove_notify_handler(dev);
1910 	mutex_unlock(&video->device_list_lock);
1911 
1912 	acpi_video_bus_stop_devices(video);
1913 	input_unregister_device(video->input);
1914 	video->input = NULL;
1915 }
1916 
1917 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1918 {
1919 	struct acpi_video_device *dev, *next;
1920 
1921 	mutex_lock(&video->device_list_lock);
1922 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1923 		list_del(&dev->entry);
1924 		kfree(dev);
1925 	}
1926 	mutex_unlock(&video->device_list_lock);
1927 
1928 	return 0;
1929 }
1930 
1931 static int instance;
1932 
1933 static int acpi_video_bus_add(struct acpi_device *device)
1934 {
1935 	struct acpi_video_bus *video;
1936 	int error;
1937 	acpi_status status;
1938 
1939 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1940 				device->parent->handle, 1,
1941 				acpi_video_bus_match, NULL,
1942 				device, NULL);
1943 	if (status == AE_ALREADY_EXISTS) {
1944 		printk(KERN_WARNING FW_BUG
1945 			"Duplicate ACPI video bus devices for the"
1946 			" same VGA controller, please try module "
1947 			"parameter \"video.allow_duplicates=1\""
1948 			"if the current driver doesn't work.\n");
1949 		if (!allow_duplicates)
1950 			return -ENODEV;
1951 	}
1952 
1953 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1954 	if (!video)
1955 		return -ENOMEM;
1956 
1957 	/* a hack to fix the duplicate name "VID" problem on T61 */
1958 	if (!strcmp(device->pnp.bus_id, "VID")) {
1959 		if (instance)
1960 			device->pnp.bus_id[3] = '0' + instance;
1961 		instance++;
1962 	}
1963 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
1964 	if (!strcmp(device->pnp.bus_id, "VGA")) {
1965 		if (instance)
1966 			device->pnp.bus_id[3] = '0' + instance;
1967 		instance++;
1968 	}
1969 
1970 	video->device = device;
1971 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
1972 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1973 	device->driver_data = video;
1974 
1975 	acpi_video_bus_find_cap(video);
1976 	error = acpi_video_bus_check(video);
1977 	if (error)
1978 		goto err_free_video;
1979 
1980 	mutex_init(&video->device_list_lock);
1981 	INIT_LIST_HEAD(&video->video_device_list);
1982 
1983 	error = acpi_video_bus_get_devices(video, device);
1984 	if (error)
1985 		goto err_put_video;
1986 
1987 	printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
1988 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
1989 	       video->flags.multihead ? "yes" : "no",
1990 	       video->flags.rom ? "yes" : "no",
1991 	       video->flags.post ? "yes" : "no");
1992 	mutex_lock(&video_list_lock);
1993 	list_add_tail(&video->entry, &video_bus_head);
1994 	mutex_unlock(&video_list_lock);
1995 
1996 	acpi_video_bus_register_backlight(video);
1997 	acpi_video_bus_add_notify_handler(video);
1998 
1999 	return 0;
2000 
2001 err_put_video:
2002 	acpi_video_bus_put_devices(video);
2003 	kfree(video->attached_array);
2004 err_free_video:
2005 	kfree(video);
2006 	device->driver_data = NULL;
2007 
2008 	return error;
2009 }
2010 
2011 static int acpi_video_bus_remove(struct acpi_device *device)
2012 {
2013 	struct acpi_video_bus *video = NULL;
2014 
2015 
2016 	if (!device || !acpi_driver_data(device))
2017 		return -EINVAL;
2018 
2019 	video = acpi_driver_data(device);
2020 
2021 	acpi_video_bus_remove_notify_handler(video);
2022 	acpi_video_bus_unregister_backlight(video);
2023 	acpi_video_bus_put_devices(video);
2024 
2025 	mutex_lock(&video_list_lock);
2026 	list_del(&video->entry);
2027 	mutex_unlock(&video_list_lock);
2028 
2029 	kfree(video->attached_array);
2030 	kfree(video);
2031 
2032 	return 0;
2033 }
2034 
2035 static int __init is_i740(struct pci_dev *dev)
2036 {
2037 	if (dev->device == 0x00D1)
2038 		return 1;
2039 	if (dev->device == 0x7000)
2040 		return 1;
2041 	return 0;
2042 }
2043 
2044 static int __init intel_opregion_present(void)
2045 {
2046 	int opregion = 0;
2047 	struct pci_dev *dev = NULL;
2048 	u32 address;
2049 
2050 	for_each_pci_dev(dev) {
2051 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2052 			continue;
2053 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2054 			continue;
2055 		/* We don't want to poke around undefined i740 registers */
2056 		if (is_i740(dev))
2057 			continue;
2058 		pci_read_config_dword(dev, 0xfc, &address);
2059 		if (!address)
2060 			continue;
2061 		opregion = 1;
2062 	}
2063 	return opregion;
2064 }
2065 
2066 int acpi_video_register(void)
2067 {
2068 	int ret = 0;
2069 
2070 	mutex_lock(&register_count_mutex);
2071 	if (register_count) {
2072 		/*
2073 		 * if the function of acpi_video_register is already called,
2074 		 * don't register the acpi_vide_bus again and return no error.
2075 		 */
2076 		goto leave;
2077 	}
2078 
2079 	dmi_check_system(video_dmi_table);
2080 
2081 	ret = acpi_bus_register_driver(&acpi_video_bus);
2082 	if (ret)
2083 		goto leave;
2084 
2085 	/*
2086 	 * When the acpi_video_bus is loaded successfully, increase
2087 	 * the counter reference.
2088 	 */
2089 	register_count = 1;
2090 
2091 leave:
2092 	mutex_unlock(&register_count_mutex);
2093 	return ret;
2094 }
2095 EXPORT_SYMBOL(acpi_video_register);
2096 
2097 void acpi_video_unregister(void)
2098 {
2099 	mutex_lock(&register_count_mutex);
2100 	if (register_count) {
2101 		acpi_bus_unregister_driver(&acpi_video_bus);
2102 		register_count = 0;
2103 	}
2104 	mutex_unlock(&register_count_mutex);
2105 }
2106 EXPORT_SYMBOL(acpi_video_unregister);
2107 
2108 void acpi_video_unregister_backlight(void)
2109 {
2110 	struct acpi_video_bus *video;
2111 
2112 	mutex_lock(&register_count_mutex);
2113 	if (register_count) {
2114 		mutex_lock(&video_list_lock);
2115 		list_for_each_entry(video, &video_bus_head, entry)
2116 			acpi_video_bus_unregister_backlight(video);
2117 		mutex_unlock(&video_list_lock);
2118 	}
2119 	mutex_unlock(&register_count_mutex);
2120 }
2121 
2122 bool acpi_video_handles_brightness_key_presses(void)
2123 {
2124 	bool have_video_busses;
2125 
2126 	mutex_lock(&video_list_lock);
2127 	have_video_busses = !list_empty(&video_bus_head);
2128 	mutex_unlock(&video_list_lock);
2129 
2130 	return have_video_busses &&
2131 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2132 }
2133 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2134 
2135 /*
2136  * This is kind of nasty. Hardware using Intel chipsets may require
2137  * the video opregion code to be run first in order to initialise
2138  * state before any ACPI video calls are made. To handle this we defer
2139  * registration of the video class until the opregion code has run.
2140  */
2141 
2142 static int __init acpi_video_init(void)
2143 {
2144 	/*
2145 	 * Let the module load even if ACPI is disabled (e.g. due to
2146 	 * a broken BIOS) so that i915.ko can still be loaded on such
2147 	 * old systems without an AcpiOpRegion.
2148 	 *
2149 	 * acpi_video_register() will report -ENODEV later as well due
2150 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2151 	 */
2152 	if (acpi_disabled)
2153 		return 0;
2154 
2155 	if (intel_opregion_present())
2156 		return 0;
2157 
2158 	return acpi_video_register();
2159 }
2160 
2161 static void __exit acpi_video_exit(void)
2162 {
2163 	acpi_video_detect_exit();
2164 	acpi_video_unregister();
2165 
2166 	return;
2167 }
2168 
2169 module_init(acpi_video_init);
2170 module_exit(acpi_video_exit);
2171