xref: /openbmc/linux/drivers/acpi/acpi_video.c (revision 65417d9f)
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 <linux/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 
47 #define MAX_NAME_LEN	20
48 
49 #define _COMPONENT		ACPI_VIDEO_COMPONENT
50 ACPI_MODULE_NAME("video");
51 
52 MODULE_AUTHOR("Bruno Ducrot");
53 MODULE_DESCRIPTION("ACPI Video Driver");
54 MODULE_LICENSE("GPL");
55 
56 static bool brightness_switch_enabled = 1;
57 module_param(brightness_switch_enabled, bool, 0644);
58 
59 /*
60  * By default, we don't allow duplicate ACPI video bus devices
61  * under the same VGA controller
62  */
63 static bool allow_duplicates;
64 module_param(allow_duplicates, bool, 0644);
65 
66 static int disable_backlight_sysfs_if = -1;
67 module_param(disable_backlight_sysfs_if, int, 0444);
68 
69 #define REPORT_OUTPUT_KEY_EVENTS		0x01
70 #define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
71 static int report_key_events = -1;
72 module_param(report_key_events, int, 0644);
73 MODULE_PARM_DESC(report_key_events,
74 	"0: none, 1: output changes, 2: brightness changes, 3: all");
75 
76 /*
77  * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be
78  * assumed even if not actually set.
79  */
80 static bool device_id_scheme = false;
81 module_param(device_id_scheme, bool, 0444);
82 
83 static bool only_lcd = false;
84 module_param(only_lcd, bool, 0444);
85 
86 static int register_count;
87 static DEFINE_MUTEX(register_count_mutex);
88 static DEFINE_MUTEX(video_list_lock);
89 static LIST_HEAD(video_bus_head);
90 static int acpi_video_bus_add(struct acpi_device *device);
91 static int acpi_video_bus_remove(struct acpi_device *device);
92 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
93 void acpi_video_detect_exit(void);
94 
95 /*
96  * Indices in the _BCL method response: the first two items are special,
97  * the rest are all supported levels.
98  *
99  * See page 575 of the ACPI spec 3.0
100  */
101 enum acpi_video_level_idx {
102 	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
103 	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
104 	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
105 };
106 
107 static const struct acpi_device_id video_device_ids[] = {
108 	{ACPI_VIDEO_HID, 0},
109 	{"", 0},
110 };
111 MODULE_DEVICE_TABLE(acpi, video_device_ids);
112 
113 static struct acpi_driver acpi_video_bus = {
114 	.name = "video",
115 	.class = ACPI_VIDEO_CLASS,
116 	.ids = video_device_ids,
117 	.ops = {
118 		.add = acpi_video_bus_add,
119 		.remove = acpi_video_bus_remove,
120 		.notify = acpi_video_bus_notify,
121 		},
122 };
123 
124 struct acpi_video_bus_flags {
125 	u8 multihead:1;		/* can switch video heads */
126 	u8 rom:1;		/* can retrieve a video rom */
127 	u8 post:1;		/* can configure the head to */
128 	u8 reserved:5;
129 };
130 
131 struct acpi_video_bus_cap {
132 	u8 _DOS:1;		/* Enable/Disable output switching */
133 	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
134 	u8 _ROM:1;		/* Get ROM Data */
135 	u8 _GPD:1;		/* Get POST Device */
136 	u8 _SPD:1;		/* Set POST Device */
137 	u8 _VPO:1;		/* Video POST Options */
138 	u8 reserved:2;
139 };
140 
141 struct acpi_video_device_attrib {
142 	u32 display_index:4;	/* A zero-based instance of the Display */
143 	u32 display_port_attachment:4;	/* This field differentiates the display type */
144 	u32 display_type:4;	/* Describe the specific type in use */
145 	u32 vendor_specific:4;	/* Chipset Vendor Specific */
146 	u32 bios_can_detect:1;	/* BIOS can detect the device */
147 	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
148 				   the VGA device. */
149 	u32 pipe_id:3;		/* For VGA multiple-head devices. */
150 	u32 reserved:10;	/* Must be 0 */
151 
152 	/*
153 	 * The device ID might not actually follow the scheme described by this
154 	 * struct acpi_video_device_attrib. If it does, then this bit
155 	 * device_id_scheme is set; otherwise, other fields should be ignored.
156 	 *
157 	 * (but also see the global flag device_id_scheme)
158 	 */
159 	u32 device_id_scheme:1;
160 };
161 
162 struct acpi_video_enumerated_device {
163 	union {
164 		u32 int_val;
165 		struct acpi_video_device_attrib attrib;
166 	} value;
167 	struct acpi_video_device *bind_info;
168 };
169 
170 struct acpi_video_bus {
171 	struct acpi_device *device;
172 	bool backlight_registered;
173 	u8 dos_setting;
174 	struct acpi_video_enumerated_device *attached_array;
175 	u8 attached_count;
176 	u8 child_count;
177 	struct acpi_video_bus_cap cap;
178 	struct acpi_video_bus_flags flags;
179 	struct list_head video_device_list;
180 	struct mutex device_list_lock;	/* protects video_device_list */
181 	struct list_head entry;
182 	struct input_dev *input;
183 	char phys[32];	/* for input device */
184 	struct notifier_block pm_nb;
185 };
186 
187 struct acpi_video_device_flags {
188 	u8 crt:1;
189 	u8 lcd:1;
190 	u8 tvout:1;
191 	u8 dvi:1;
192 	u8 bios:1;
193 	u8 unknown:1;
194 	u8 notify:1;
195 	u8 reserved:1;
196 };
197 
198 struct acpi_video_device_cap {
199 	u8 _ADR:1;		/* Return the unique ID */
200 	u8 _BCL:1;		/* Query list of brightness control levels supported */
201 	u8 _BCM:1;		/* Set the brightness level */
202 	u8 _BQC:1;		/* Get current brightness level */
203 	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
204 	u8 _DDC:1;		/* Return the EDID for this device */
205 };
206 
207 struct acpi_video_device {
208 	unsigned long device_id;
209 	struct acpi_video_device_flags flags;
210 	struct acpi_video_device_cap cap;
211 	struct list_head entry;
212 	struct delayed_work switch_brightness_work;
213 	int switch_brightness_event;
214 	struct acpi_video_bus *video;
215 	struct acpi_device *dev;
216 	struct acpi_video_device_brightness *brightness;
217 	struct backlight_device *backlight;
218 	struct thermal_cooling_device *cooling_dev;
219 };
220 
221 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
222 static void acpi_video_device_rebind(struct acpi_video_bus *video);
223 static void acpi_video_device_bind(struct acpi_video_bus *video,
224 				   struct acpi_video_device *device);
225 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
226 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
227 			int level);
228 static int acpi_video_device_lcd_get_level_current(
229 			struct acpi_video_device *device,
230 			unsigned long long *level, bool raw);
231 static int acpi_video_get_next_level(struct acpi_video_device *device,
232 				     u32 level_current, u32 event);
233 static void acpi_video_switch_brightness(struct work_struct *work);
234 
235 /* backlight device sysfs support */
236 static int acpi_video_get_brightness(struct backlight_device *bd)
237 {
238 	unsigned long long cur_level;
239 	int i;
240 	struct acpi_video_device *vd = bl_get_data(bd);
241 
242 	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
243 		return -EINVAL;
244 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
245 		if (vd->brightness->levels[i] == cur_level)
246 			return i - ACPI_VIDEO_FIRST_LEVEL;
247 	}
248 	return 0;
249 }
250 
251 static int acpi_video_set_brightness(struct backlight_device *bd)
252 {
253 	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
254 	struct acpi_video_device *vd = bl_get_data(bd);
255 
256 	cancel_delayed_work(&vd->switch_brightness_work);
257 	return acpi_video_device_lcd_set_level(vd,
258 				vd->brightness->levels[request_level]);
259 }
260 
261 static const struct backlight_ops acpi_backlight_ops = {
262 	.get_brightness = acpi_video_get_brightness,
263 	.update_status  = acpi_video_set_brightness,
264 };
265 
266 /* thermal cooling device callbacks */
267 static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
268 			       unsigned long *state)
269 {
270 	struct acpi_device *device = cooling_dev->devdata;
271 	struct acpi_video_device *video = acpi_driver_data(device);
272 
273 	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
274 	return 0;
275 }
276 
277 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
278 			       unsigned long *state)
279 {
280 	struct acpi_device *device = cooling_dev->devdata;
281 	struct acpi_video_device *video = acpi_driver_data(device);
282 	unsigned long long level;
283 	int offset;
284 
285 	if (acpi_video_device_lcd_get_level_current(video, &level, false))
286 		return -EINVAL;
287 	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
288 	     offset++)
289 		if (level == video->brightness->levels[offset]) {
290 			*state = video->brightness->count - offset - 1;
291 			return 0;
292 		}
293 
294 	return -EINVAL;
295 }
296 
297 static int
298 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
299 {
300 	struct acpi_device *device = cooling_dev->devdata;
301 	struct acpi_video_device *video = acpi_driver_data(device);
302 	int level;
303 
304 	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
305 		return -EINVAL;
306 
307 	state = video->brightness->count - state;
308 	level = video->brightness->levels[state - 1];
309 	return acpi_video_device_lcd_set_level(video, level);
310 }
311 
312 static const struct thermal_cooling_device_ops video_cooling_ops = {
313 	.get_max_state = video_get_max_state,
314 	.get_cur_state = video_get_cur_state,
315 	.set_cur_state = video_set_cur_state,
316 };
317 
318 /*
319  * --------------------------------------------------------------------------
320  *                             Video Management
321  * --------------------------------------------------------------------------
322  */
323 
324 static int
325 acpi_video_device_lcd_query_levels(acpi_handle handle,
326 				   union acpi_object **levels)
327 {
328 	int status;
329 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
330 	union acpi_object *obj;
331 
332 
333 	*levels = NULL;
334 
335 	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
336 	if (!ACPI_SUCCESS(status))
337 		return status;
338 	obj = (union acpi_object *)buffer.pointer;
339 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
340 		printk(KERN_ERR PREFIX "Invalid _BCL data\n");
341 		status = -EFAULT;
342 		goto err;
343 	}
344 
345 	*levels = obj;
346 
347 	return 0;
348 
349 err:
350 	kfree(buffer.pointer);
351 
352 	return status;
353 }
354 
355 static int
356 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
357 {
358 	int status;
359 	int state;
360 
361 	status = acpi_execute_simple_method(device->dev->handle,
362 					    "_BCM", level);
363 	if (ACPI_FAILURE(status)) {
364 		ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
365 		return -EIO;
366 	}
367 
368 	device->brightness->curr = level;
369 	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
370 	     state++)
371 		if (level == device->brightness->levels[state]) {
372 			if (device->backlight)
373 				device->backlight->props.brightness =
374 					state - ACPI_VIDEO_FIRST_LEVEL;
375 			return 0;
376 		}
377 
378 	ACPI_ERROR((AE_INFO, "Current brightness invalid"));
379 	return -EINVAL;
380 }
381 
382 /*
383  * For some buggy _BQC methods, we need to add a constant value to
384  * the _BQC return value to get the actual current brightness level
385  */
386 
387 static int bqc_offset_aml_bug_workaround;
388 static int video_set_bqc_offset(const struct dmi_system_id *d)
389 {
390 	bqc_offset_aml_bug_workaround = 9;
391 	return 0;
392 }
393 
394 static int video_disable_backlight_sysfs_if(
395 	const struct dmi_system_id *d)
396 {
397 	if (disable_backlight_sysfs_if == -1)
398 		disable_backlight_sysfs_if = 1;
399 	return 0;
400 }
401 
402 static int video_set_device_id_scheme(const struct dmi_system_id *d)
403 {
404 	device_id_scheme = true;
405 	return 0;
406 }
407 
408 static int video_enable_only_lcd(const struct dmi_system_id *d)
409 {
410 	only_lcd = true;
411 	return 0;
412 }
413 
414 static int video_set_report_key_events(const struct dmi_system_id *id)
415 {
416 	if (report_key_events == -1)
417 		report_key_events = (uintptr_t)id->driver_data;
418 	return 0;
419 }
420 
421 static const struct dmi_system_id video_dmi_table[] = {
422 	/*
423 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
424 	 */
425 	{
426 	 .callback = video_set_bqc_offset,
427 	 .ident = "Acer Aspire 5720",
428 	 .matches = {
429 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
430 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
431 		},
432 	},
433 	{
434 	 .callback = video_set_bqc_offset,
435 	 .ident = "Acer Aspire 5710Z",
436 	 .matches = {
437 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
438 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
439 		},
440 	},
441 	{
442 	 .callback = video_set_bqc_offset,
443 	 .ident = "eMachines E510",
444 	 .matches = {
445 		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
446 		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
447 		},
448 	},
449 	{
450 	 .callback = video_set_bqc_offset,
451 	 .ident = "Acer Aspire 5315",
452 	 .matches = {
453 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
454 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
455 		},
456 	},
457 	{
458 	 .callback = video_set_bqc_offset,
459 	 .ident = "Acer Aspire 7720",
460 	 .matches = {
461 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
462 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
463 		},
464 	},
465 
466 	/*
467 	 * Some machines have a broken acpi-video interface for brightness
468 	 * control, but still need an acpi_video_device_lcd_set_level() call
469 	 * on resume to turn the backlight power on.  We Enable backlight
470 	 * control on these systems, but do not register a backlight sysfs
471 	 * as brightness control does not work.
472 	 */
473 	{
474 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
475 	 .callback = video_disable_backlight_sysfs_if,
476 	 .ident = "Toshiba Portege R700",
477 	 .matches = {
478 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
479 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
480 		},
481 	},
482 	{
483 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
484 	 .callback = video_disable_backlight_sysfs_if,
485 	 .ident = "Toshiba Portege R830",
486 	 .matches = {
487 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
488 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
489 		},
490 	},
491 	{
492 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
493 	 .callback = video_disable_backlight_sysfs_if,
494 	 .ident = "Toshiba Satellite R830",
495 	 .matches = {
496 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
497 		DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
498 		},
499 	},
500 	/*
501 	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
502 	 * but the IDs actually follow the Device ID Scheme.
503 	 */
504 	{
505 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
506 	 .callback = video_set_device_id_scheme,
507 	 .ident = "ESPRIMO Mobile M9410",
508 	 .matches = {
509 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
510 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
511 		},
512 	},
513 	/*
514 	 * Some machines have multiple video output devices, but only the one
515 	 * that is the type of LCD can do the backlight control so we should not
516 	 * register backlight interface for other video output devices.
517 	 */
518 	{
519 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
520 	 .callback = video_enable_only_lcd,
521 	 .ident = "ESPRIMO Mobile M9410",
522 	 .matches = {
523 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
524 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
525 		},
526 	},
527 	/*
528 	 * Some machines report wrong key events on the acpi-bus, suppress
529 	 * key event reporting on these.  Note this is only intended to work
530 	 * around events which are plain wrong. In some cases we get double
531 	 * events, in this case acpi-video is considered the canonical source
532 	 * and the events from the other source should be filtered. E.g.
533 	 * by calling acpi_video_handles_brightness_key_presses() from the
534 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
535 	 */
536 	{
537 	 .callback = video_set_report_key_events,
538 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
539 	 .ident = "Dell Vostro V131",
540 	 .matches = {
541 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
542 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
543 		},
544 	},
545 	{}
546 };
547 
548 static unsigned long long
549 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
550 			      unsigned long long bqc_value)
551 {
552 	unsigned long long level;
553 
554 	if (device->brightness->flags._BQC_use_index) {
555 		/*
556 		 * _BQC returns an index that doesn't account for the first 2
557 		 * items with special meaning (see enum acpi_video_level_idx),
558 		 * so we need to compensate for that by offsetting ourselves
559 		 */
560 		if (device->brightness->flags._BCL_reversed)
561 			bqc_value = device->brightness->count -
562 				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
563 
564 		level = device->brightness->levels[bqc_value +
565 		                                   ACPI_VIDEO_FIRST_LEVEL];
566 	} else {
567 		level = bqc_value;
568 	}
569 
570 	level += bqc_offset_aml_bug_workaround;
571 
572 	return level;
573 }
574 
575 static int
576 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
577 					unsigned long long *level, bool raw)
578 {
579 	acpi_status status = AE_OK;
580 	int i;
581 
582 	if (device->cap._BQC || device->cap._BCQ) {
583 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
584 
585 		status = acpi_evaluate_integer(device->dev->handle, buf,
586 						NULL, level);
587 		if (ACPI_SUCCESS(status)) {
588 			if (raw) {
589 				/*
590 				 * Caller has indicated he wants the raw
591 				 * value returned by _BQC, so don't furtherly
592 				 * mess with the value.
593 				 */
594 				return 0;
595 			}
596 
597 			*level = acpi_video_bqc_value_to_level(device, *level);
598 
599 			for (i = ACPI_VIDEO_FIRST_LEVEL;
600 			     i < device->brightness->count; i++)
601 				if (device->brightness->levels[i] == *level) {
602 					device->brightness->curr = *level;
603 					return 0;
604 				}
605 			/*
606 			 * BQC returned an invalid level.
607 			 * Stop using it.
608 			 */
609 			ACPI_WARNING((AE_INFO,
610 				      "%s returned an invalid level",
611 				      buf));
612 			device->cap._BQC = device->cap._BCQ = 0;
613 		} else {
614 			/*
615 			 * Fixme:
616 			 * should we return an error or ignore this failure?
617 			 * dev->brightness->curr is a cached value which stores
618 			 * the correct current backlight level in most cases.
619 			 * ACPI video backlight still works w/ buggy _BQC.
620 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
621 			 */
622 			ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
623 			device->cap._BQC = device->cap._BCQ = 0;
624 		}
625 	}
626 
627 	*level = device->brightness->curr;
628 	return 0;
629 }
630 
631 static int
632 acpi_video_device_EDID(struct acpi_video_device *device,
633 		       union acpi_object **edid, ssize_t length)
634 {
635 	int status;
636 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
637 	union acpi_object *obj;
638 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
639 	struct acpi_object_list args = { 1, &arg0 };
640 
641 
642 	*edid = NULL;
643 
644 	if (!device)
645 		return -ENODEV;
646 	if (length == 128)
647 		arg0.integer.value = 1;
648 	else if (length == 256)
649 		arg0.integer.value = 2;
650 	else
651 		return -EINVAL;
652 
653 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
654 	if (ACPI_FAILURE(status))
655 		return -ENODEV;
656 
657 	obj = buffer.pointer;
658 
659 	if (obj && obj->type == ACPI_TYPE_BUFFER)
660 		*edid = obj;
661 	else {
662 		printk(KERN_ERR PREFIX "Invalid _DDC data\n");
663 		status = -EFAULT;
664 		kfree(obj);
665 	}
666 
667 	return status;
668 }
669 
670 /* bus */
671 
672 /*
673  *  Arg:
674  *	video		: video bus device pointer
675  *	bios_flag	:
676  *		0.	The system BIOS should NOT automatically switch(toggle)
677  *			the active display output.
678  *		1.	The system BIOS should automatically switch (toggle) the
679  *			active display output. No switch event.
680  *		2.	The _DGS value should be locked.
681  *		3.	The system BIOS should not automatically switch (toggle) the
682  *			active display output, but instead generate the display switch
683  *			event notify code.
684  *	lcd_flag	:
685  *		0.	The system BIOS should automatically control the brightness level
686  *			of the LCD when the power changes from AC to DC
687  *		1.	The system BIOS should NOT automatically control the brightness
688  *			level of the LCD when the power changes from AC to DC.
689  *  Return Value:
690  *		-EINVAL	wrong arg.
691  */
692 
693 static int
694 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
695 {
696 	acpi_status status;
697 
698 	if (!video->cap._DOS)
699 		return 0;
700 
701 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
702 		return -EINVAL;
703 	video->dos_setting = (lcd_flag << 2) | bios_flag;
704 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
705 					    (lcd_flag << 2) | bios_flag);
706 	if (ACPI_FAILURE(status))
707 		return -EIO;
708 
709 	return 0;
710 }
711 
712 /*
713  * Simple comparison function used to sort backlight levels.
714  */
715 
716 static int
717 acpi_video_cmp_level(const void *a, const void *b)
718 {
719 	return *(int *)a - *(int *)b;
720 }
721 
722 /*
723  * Decides if _BQC/_BCQ for this system is usable
724  *
725  * We do this by changing the level first and then read out the current
726  * brightness level, if the value does not match, find out if it is using
727  * index. If not, clear the _BQC/_BCQ capability.
728  */
729 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
730 				int max_level, int current_level)
731 {
732 	struct acpi_video_device_brightness *br = device->brightness;
733 	int result;
734 	unsigned long long level;
735 	int test_level;
736 
737 	/* don't mess with existing known broken systems */
738 	if (bqc_offset_aml_bug_workaround)
739 		return 0;
740 
741 	/*
742 	 * Some systems always report current brightness level as maximum
743 	 * through _BQC, we need to test another value for them. However,
744 	 * there is a subtlety:
745 	 *
746 	 * If the _BCL package ordering is descending, the first level
747 	 * (br->levels[2]) is likely to be 0, and if the number of levels
748 	 * matches the number of steps, we might confuse a returned level to
749 	 * mean the index.
750 	 *
751 	 * For example:
752 	 *
753 	 *     current_level = max_level = 100
754 	 *     test_level = 0
755 	 *     returned level = 100
756 	 *
757 	 * In this case 100 means the level, not the index, and _BCM failed.
758 	 * Still, if the _BCL package ordering is descending, the index of
759 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
760 	 *
761 	 * This causes all _BQC calls to return bogus values causing weird
762 	 * behavior from the user's perspective.  For example:
763 	 *
764 	 * xbacklight -set 10; xbacklight -set 20;
765 	 *
766 	 * would flash to 90% and then slowly down to the desired level (20).
767 	 *
768 	 * The solution is simple; test anything other than the first level
769 	 * (e.g. 1).
770 	 */
771 	test_level = current_level == max_level
772 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
773 		: max_level;
774 
775 	result = acpi_video_device_lcd_set_level(device, test_level);
776 	if (result)
777 		return result;
778 
779 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
780 	if (result)
781 		return result;
782 
783 	if (level != test_level) {
784 		/* buggy _BQC found, need to find out if it uses index */
785 		if (level < br->count) {
786 			if (br->flags._BCL_reversed)
787 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
788 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
789 				br->flags._BQC_use_index = 1;
790 		}
791 
792 		if (!br->flags._BQC_use_index)
793 			device->cap._BQC = device->cap._BCQ = 0;
794 	}
795 
796 	return 0;
797 }
798 
799 int acpi_video_get_levels(struct acpi_device *device,
800 			  struct acpi_video_device_brightness **dev_br,
801 			  int *pmax_level)
802 {
803 	union acpi_object *obj = NULL;
804 	int i, max_level = 0, count = 0, level_ac_battery = 0;
805 	union acpi_object *o;
806 	struct acpi_video_device_brightness *br = NULL;
807 	int result = 0;
808 	u32 value;
809 
810 	if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device->handle,
811 								&obj))) {
812 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
813 						"LCD brightness level\n"));
814 		result = -ENODEV;
815 		goto out;
816 	}
817 
818 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
819 		result = -EINVAL;
820 		goto out;
821 	}
822 
823 	br = kzalloc(sizeof(*br), GFP_KERNEL);
824 	if (!br) {
825 		printk(KERN_ERR "can't allocate memory\n");
826 		result = -ENOMEM;
827 		goto out;
828 	}
829 
830 	/*
831 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
832 	 * in order to account for buggy BIOS which don't export the first two
833 	 * special levels (see below)
834 	 */
835 	br->levels = kmalloc((obj->package.count + ACPI_VIDEO_FIRST_LEVEL) *
836 	                     sizeof(*br->levels), GFP_KERNEL);
837 	if (!br->levels) {
838 		result = -ENOMEM;
839 		goto out_free;
840 	}
841 
842 	for (i = 0; i < obj->package.count; i++) {
843 		o = (union acpi_object *)&obj->package.elements[i];
844 		if (o->type != ACPI_TYPE_INTEGER) {
845 			printk(KERN_ERR PREFIX "Invalid data\n");
846 			continue;
847 		}
848 		value = (u32) o->integer.value;
849 		/* Skip duplicate entries */
850 		if (count > ACPI_VIDEO_FIRST_LEVEL
851 		    && br->levels[count - 1] == value)
852 			continue;
853 
854 		br->levels[count] = value;
855 
856 		if (br->levels[count] > max_level)
857 			max_level = br->levels[count];
858 		count++;
859 	}
860 
861 	/*
862 	 * some buggy BIOS don't export the levels
863 	 * when machine is on AC/Battery in _BCL package.
864 	 * In this case, the first two elements in _BCL packages
865 	 * are also supported brightness levels that OS should take care of.
866 	 */
867 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
868 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
869 			level_ac_battery++;
870 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
871 			level_ac_battery++;
872 	}
873 
874 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
875 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
876 		br->flags._BCL_no_ac_battery_levels = 1;
877 		for (i = (count - 1 + level_ac_battery);
878 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
879 			br->levels[i] = br->levels[i - level_ac_battery];
880 		count += level_ac_battery;
881 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
882 		ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
883 
884 	/* Check if the _BCL package is in a reversed order */
885 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
886 		br->flags._BCL_reversed = 1;
887 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
888 		     count - ACPI_VIDEO_FIRST_LEVEL,
889 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
890 		     acpi_video_cmp_level, NULL);
891 	} else if (max_level != br->levels[count - 1])
892 		ACPI_ERROR((AE_INFO,
893 			    "Found unordered _BCL package"));
894 
895 	br->count = count;
896 	*dev_br = br;
897 	if (pmax_level)
898 		*pmax_level = max_level;
899 
900 out:
901 	kfree(obj);
902 	return result;
903 out_free:
904 	kfree(br);
905 	goto out;
906 }
907 EXPORT_SYMBOL(acpi_video_get_levels);
908 
909 /*
910  *  Arg:
911  *	device	: video output device (LCD, CRT, ..)
912  *
913  *  Return Value:
914  *	Maximum brightness level
915  *
916  *  Allocate and initialize device->brightness.
917  */
918 
919 static int
920 acpi_video_init_brightness(struct acpi_video_device *device)
921 {
922 	int i, max_level = 0;
923 	unsigned long long level, level_old;
924 	struct acpi_video_device_brightness *br = NULL;
925 	int result = -EINVAL;
926 
927 	result = acpi_video_get_levels(device->dev, &br, &max_level);
928 	if (result)
929 		return result;
930 	device->brightness = br;
931 
932 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
933 	br->curr = level = max_level;
934 
935 	if (!device->cap._BQC)
936 		goto set_level;
937 
938 	result = acpi_video_device_lcd_get_level_current(device,
939 							 &level_old, true);
940 	if (result)
941 		goto out_free_levels;
942 
943 	result = acpi_video_bqc_quirk(device, max_level, level_old);
944 	if (result)
945 		goto out_free_levels;
946 	/*
947 	 * cap._BQC may get cleared due to _BQC is found to be broken
948 	 * in acpi_video_bqc_quirk, so check again here.
949 	 */
950 	if (!device->cap._BQC)
951 		goto set_level;
952 
953 	level = acpi_video_bqc_value_to_level(device, level_old);
954 	/*
955 	 * On some buggy laptops, _BQC returns an uninitialized
956 	 * value when invoked for the first time, i.e.
957 	 * level_old is invalid (no matter whether it's a level
958 	 * or an index). Set the backlight to max_level in this case.
959 	 */
960 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
961 		if (level == br->levels[i])
962 			break;
963 	if (i == br->count || !level)
964 		level = max_level;
965 
966 set_level:
967 	result = acpi_video_device_lcd_set_level(device, level);
968 	if (result)
969 		goto out_free_levels;
970 
971 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
972 	                  "found %d brightness levels\n",
973 	                  br->count - ACPI_VIDEO_FIRST_LEVEL));
974 	return 0;
975 
976 out_free_levels:
977 	kfree(br->levels);
978 	kfree(br);
979 	device->brightness = NULL;
980 	return result;
981 }
982 
983 /*
984  *  Arg:
985  *	device	: video output device (LCD, CRT, ..)
986  *
987  *  Return Value:
988  *	None
989  *
990  *  Find out all required AML methods defined under the output
991  *  device.
992  */
993 
994 static void acpi_video_device_find_cap(struct acpi_video_device *device)
995 {
996 	if (acpi_has_method(device->dev->handle, "_ADR"))
997 		device->cap._ADR = 1;
998 	if (acpi_has_method(device->dev->handle, "_BCL"))
999 		device->cap._BCL = 1;
1000 	if (acpi_has_method(device->dev->handle, "_BCM"))
1001 		device->cap._BCM = 1;
1002 	if (acpi_has_method(device->dev->handle, "_BQC")) {
1003 		device->cap._BQC = 1;
1004 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
1005 		printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
1006 		device->cap._BCQ = 1;
1007 	}
1008 
1009 	if (acpi_has_method(device->dev->handle, "_DDC"))
1010 		device->cap._DDC = 1;
1011 }
1012 
1013 /*
1014  *  Arg:
1015  *	device	: video output device (VGA)
1016  *
1017  *  Return Value:
1018  *	None
1019  *
1020  *  Find out all required AML methods defined under the video bus device.
1021  */
1022 
1023 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1024 {
1025 	if (acpi_has_method(video->device->handle, "_DOS"))
1026 		video->cap._DOS = 1;
1027 	if (acpi_has_method(video->device->handle, "_DOD"))
1028 		video->cap._DOD = 1;
1029 	if (acpi_has_method(video->device->handle, "_ROM"))
1030 		video->cap._ROM = 1;
1031 	if (acpi_has_method(video->device->handle, "_GPD"))
1032 		video->cap._GPD = 1;
1033 	if (acpi_has_method(video->device->handle, "_SPD"))
1034 		video->cap._SPD = 1;
1035 	if (acpi_has_method(video->device->handle, "_VPO"))
1036 		video->cap._VPO = 1;
1037 }
1038 
1039 /*
1040  * Check whether the video bus device has required AML method to
1041  * support the desired features
1042  */
1043 
1044 static int acpi_video_bus_check(struct acpi_video_bus *video)
1045 {
1046 	acpi_status status = -ENOENT;
1047 	struct pci_dev *dev;
1048 
1049 	if (!video)
1050 		return -EINVAL;
1051 
1052 	dev = acpi_get_pci_dev(video->device->handle);
1053 	if (!dev)
1054 		return -ENODEV;
1055 	pci_dev_put(dev);
1056 
1057 	/*
1058 	 * Since there is no HID, CID and so on for VGA driver, we have
1059 	 * to check well known required nodes.
1060 	 */
1061 
1062 	/* Does this device support video switching? */
1063 	if (video->cap._DOS || video->cap._DOD) {
1064 		if (!video->cap._DOS) {
1065 			printk(KERN_WARNING FW_BUG
1066 				"ACPI(%s) defines _DOD but not _DOS\n",
1067 				acpi_device_bid(video->device));
1068 		}
1069 		video->flags.multihead = 1;
1070 		status = 0;
1071 	}
1072 
1073 	/* Does this device support retrieving a video ROM? */
1074 	if (video->cap._ROM) {
1075 		video->flags.rom = 1;
1076 		status = 0;
1077 	}
1078 
1079 	/* Does this device support configuring which video device to POST? */
1080 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1081 		video->flags.post = 1;
1082 		status = 0;
1083 	}
1084 
1085 	return status;
1086 }
1087 
1088 /*
1089  * --------------------------------------------------------------------------
1090  *                               Driver Interface
1091  * --------------------------------------------------------------------------
1092  */
1093 
1094 /* device interface */
1095 static struct acpi_video_device_attrib *
1096 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1097 {
1098 	struct acpi_video_enumerated_device *ids;
1099 	int i;
1100 
1101 	for (i = 0; i < video->attached_count; i++) {
1102 		ids = &video->attached_array[i];
1103 		if ((ids->value.int_val & 0xffff) == device_id)
1104 			return &ids->value.attrib;
1105 	}
1106 
1107 	return NULL;
1108 }
1109 
1110 static int
1111 acpi_video_get_device_type(struct acpi_video_bus *video,
1112 			   unsigned long device_id)
1113 {
1114 	struct acpi_video_enumerated_device *ids;
1115 	int i;
1116 
1117 	for (i = 0; i < video->attached_count; i++) {
1118 		ids = &video->attached_array[i];
1119 		if ((ids->value.int_val & 0xffff) == device_id)
1120 			return ids->value.int_val;
1121 	}
1122 
1123 	return 0;
1124 }
1125 
1126 static int
1127 acpi_video_bus_get_one_device(struct acpi_device *device,
1128 			      struct acpi_video_bus *video)
1129 {
1130 	unsigned long long device_id;
1131 	int status, device_type;
1132 	struct acpi_video_device *data;
1133 	struct acpi_video_device_attrib *attribute;
1134 
1135 	status =
1136 	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1137 	/* Some device omits _ADR, we skip them instead of fail */
1138 	if (ACPI_FAILURE(status))
1139 		return 0;
1140 
1141 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1142 	if (!data)
1143 		return -ENOMEM;
1144 
1145 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1146 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1147 	device->driver_data = data;
1148 
1149 	data->device_id = device_id;
1150 	data->video = video;
1151 	data->dev = device;
1152 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1153 			  acpi_video_switch_brightness);
1154 
1155 	attribute = acpi_video_get_device_attr(video, device_id);
1156 
1157 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1158 		switch (attribute->display_type) {
1159 		case ACPI_VIDEO_DISPLAY_CRT:
1160 			data->flags.crt = 1;
1161 			break;
1162 		case ACPI_VIDEO_DISPLAY_TV:
1163 			data->flags.tvout = 1;
1164 			break;
1165 		case ACPI_VIDEO_DISPLAY_DVI:
1166 			data->flags.dvi = 1;
1167 			break;
1168 		case ACPI_VIDEO_DISPLAY_LCD:
1169 			data->flags.lcd = 1;
1170 			break;
1171 		default:
1172 			data->flags.unknown = 1;
1173 			break;
1174 		}
1175 		if (attribute->bios_can_detect)
1176 			data->flags.bios = 1;
1177 	} else {
1178 		/* Check for legacy IDs */
1179 		device_type = acpi_video_get_device_type(video, device_id);
1180 		/* Ignore bits 16 and 18-20 */
1181 		switch (device_type & 0xffe2ffff) {
1182 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1183 			data->flags.crt = 1;
1184 			break;
1185 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1186 			data->flags.lcd = 1;
1187 			break;
1188 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1189 			data->flags.tvout = 1;
1190 			break;
1191 		default:
1192 			data->flags.unknown = 1;
1193 		}
1194 	}
1195 
1196 	acpi_video_device_bind(video, data);
1197 	acpi_video_device_find_cap(data);
1198 
1199 	mutex_lock(&video->device_list_lock);
1200 	list_add_tail(&data->entry, &video->video_device_list);
1201 	mutex_unlock(&video->device_list_lock);
1202 
1203 	return status;
1204 }
1205 
1206 /*
1207  *  Arg:
1208  *	video	: video bus device
1209  *
1210  *  Return:
1211  *	none
1212  *
1213  *  Enumerate the video device list of the video bus,
1214  *  bind the ids with the corresponding video devices
1215  *  under the video bus.
1216  */
1217 
1218 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1219 {
1220 	struct acpi_video_device *dev;
1221 
1222 	mutex_lock(&video->device_list_lock);
1223 
1224 	list_for_each_entry(dev, &video->video_device_list, entry)
1225 		acpi_video_device_bind(video, dev);
1226 
1227 	mutex_unlock(&video->device_list_lock);
1228 }
1229 
1230 /*
1231  *  Arg:
1232  *	video	: video bus device
1233  *	device	: video output device under the video
1234  *		bus
1235  *
1236  *  Return:
1237  *	none
1238  *
1239  *  Bind the ids with the corresponding video devices
1240  *  under the video bus.
1241  */
1242 
1243 static void
1244 acpi_video_device_bind(struct acpi_video_bus *video,
1245 		       struct acpi_video_device *device)
1246 {
1247 	struct acpi_video_enumerated_device *ids;
1248 	int i;
1249 
1250 	for (i = 0; i < video->attached_count; i++) {
1251 		ids = &video->attached_array[i];
1252 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1253 			ids->bind_info = device;
1254 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1255 		}
1256 	}
1257 }
1258 
1259 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1260 {
1261 	struct acpi_video_bus *video = device->video;
1262 	int i;
1263 
1264 	/*
1265 	 * If we have a broken _DOD or we have more than 8 output devices
1266 	 * under the graphics controller node that we can't proper deal with
1267 	 * in the operation region code currently, no need to test.
1268 	 */
1269 	if (!video->attached_count || video->child_count > 8)
1270 		return true;
1271 
1272 	for (i = 0; i < video->attached_count; i++) {
1273 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1274 		    (device->device_id & 0xfff))
1275 			return true;
1276 	}
1277 
1278 	return false;
1279 }
1280 
1281 /*
1282  *  Arg:
1283  *	video	: video bus device
1284  *
1285  *  Return:
1286  *	< 0	: error
1287  *
1288  *  Call _DOD to enumerate all devices attached to display adapter
1289  *
1290  */
1291 
1292 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1293 {
1294 	int status;
1295 	int count;
1296 	int i;
1297 	struct acpi_video_enumerated_device *active_list;
1298 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1299 	union acpi_object *dod = NULL;
1300 	union acpi_object *obj;
1301 
1302 	if (!video->cap._DOD)
1303 		return AE_NOT_EXIST;
1304 
1305 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1306 	if (!ACPI_SUCCESS(status)) {
1307 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1308 		return status;
1309 	}
1310 
1311 	dod = buffer.pointer;
1312 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1313 		ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1314 		status = -EFAULT;
1315 		goto out;
1316 	}
1317 
1318 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1319 			  dod->package.count));
1320 
1321 	active_list = kcalloc(1 + dod->package.count,
1322 			      sizeof(struct acpi_video_enumerated_device),
1323 			      GFP_KERNEL);
1324 	if (!active_list) {
1325 		status = -ENOMEM;
1326 		goto out;
1327 	}
1328 
1329 	count = 0;
1330 	for (i = 0; i < dod->package.count; i++) {
1331 		obj = &dod->package.elements[i];
1332 
1333 		if (obj->type != ACPI_TYPE_INTEGER) {
1334 			printk(KERN_ERR PREFIX
1335 				"Invalid _DOD data in element %d\n", i);
1336 			continue;
1337 		}
1338 
1339 		active_list[count].value.int_val = obj->integer.value;
1340 		active_list[count].bind_info = NULL;
1341 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1342 				  (int)obj->integer.value));
1343 		count++;
1344 	}
1345 
1346 	kfree(video->attached_array);
1347 
1348 	video->attached_array = active_list;
1349 	video->attached_count = count;
1350 
1351 out:
1352 	kfree(buffer.pointer);
1353 	return status;
1354 }
1355 
1356 static int
1357 acpi_video_get_next_level(struct acpi_video_device *device,
1358 			  u32 level_current, u32 event)
1359 {
1360 	int min, max, min_above, max_below, i, l, delta = 255;
1361 	max = max_below = 0;
1362 	min = min_above = 255;
1363 	/* Find closest level to level_current */
1364 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1365 		l = device->brightness->levels[i];
1366 		if (abs(l - level_current) < abs(delta)) {
1367 			delta = l - level_current;
1368 			if (!delta)
1369 				break;
1370 		}
1371 	}
1372 	/* Ajust level_current to closest available level */
1373 	level_current += delta;
1374 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1375 		l = device->brightness->levels[i];
1376 		if (l < min)
1377 			min = l;
1378 		if (l > max)
1379 			max = l;
1380 		if (l < min_above && l > level_current)
1381 			min_above = l;
1382 		if (l > max_below && l < level_current)
1383 			max_below = l;
1384 	}
1385 
1386 	switch (event) {
1387 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1388 		return (level_current < max) ? min_above : min;
1389 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1390 		return (level_current < max) ? min_above : max;
1391 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1392 		return (level_current > min) ? max_below : min;
1393 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1394 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1395 		return 0;
1396 	default:
1397 		return level_current;
1398 	}
1399 }
1400 
1401 static void
1402 acpi_video_switch_brightness(struct work_struct *work)
1403 {
1404 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1405 			     struct acpi_video_device, switch_brightness_work);
1406 	unsigned long long level_current, level_next;
1407 	int event = device->switch_brightness_event;
1408 	int result = -EINVAL;
1409 
1410 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1411 	if (!device->backlight)
1412 		return;
1413 
1414 	if (!device->brightness)
1415 		goto out;
1416 
1417 	result = acpi_video_device_lcd_get_level_current(device,
1418 							 &level_current,
1419 							 false);
1420 	if (result)
1421 		goto out;
1422 
1423 	level_next = acpi_video_get_next_level(device, level_current, event);
1424 
1425 	result = acpi_video_device_lcd_set_level(device, level_next);
1426 
1427 	if (!result)
1428 		backlight_force_update(device->backlight,
1429 				       BACKLIGHT_UPDATE_HOTKEY);
1430 
1431 out:
1432 	if (result)
1433 		printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1434 }
1435 
1436 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1437 			void **edid)
1438 {
1439 	struct acpi_video_bus *video;
1440 	struct acpi_video_device *video_device;
1441 	union acpi_object *buffer = NULL;
1442 	acpi_status status;
1443 	int i, length;
1444 
1445 	if (!device || !acpi_driver_data(device))
1446 		return -EINVAL;
1447 
1448 	video = acpi_driver_data(device);
1449 
1450 	for (i = 0; i < video->attached_count; i++) {
1451 		video_device = video->attached_array[i].bind_info;
1452 		length = 256;
1453 
1454 		if (!video_device)
1455 			continue;
1456 
1457 		if (!video_device->cap._DDC)
1458 			continue;
1459 
1460 		if (type) {
1461 			switch (type) {
1462 			case ACPI_VIDEO_DISPLAY_CRT:
1463 				if (!video_device->flags.crt)
1464 					continue;
1465 				break;
1466 			case ACPI_VIDEO_DISPLAY_TV:
1467 				if (!video_device->flags.tvout)
1468 					continue;
1469 				break;
1470 			case ACPI_VIDEO_DISPLAY_DVI:
1471 				if (!video_device->flags.dvi)
1472 					continue;
1473 				break;
1474 			case ACPI_VIDEO_DISPLAY_LCD:
1475 				if (!video_device->flags.lcd)
1476 					continue;
1477 				break;
1478 			}
1479 		} else if (video_device->device_id != device_id) {
1480 			continue;
1481 		}
1482 
1483 		status = acpi_video_device_EDID(video_device, &buffer, length);
1484 
1485 		if (ACPI_FAILURE(status) || !buffer ||
1486 		    buffer->type != ACPI_TYPE_BUFFER) {
1487 			length = 128;
1488 			status = acpi_video_device_EDID(video_device, &buffer,
1489 							length);
1490 			if (ACPI_FAILURE(status) || !buffer ||
1491 			    buffer->type != ACPI_TYPE_BUFFER) {
1492 				continue;
1493 			}
1494 		}
1495 
1496 		*edid = buffer->buffer.pointer;
1497 		return length;
1498 	}
1499 
1500 	return -ENODEV;
1501 }
1502 EXPORT_SYMBOL(acpi_video_get_edid);
1503 
1504 static int
1505 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1506 			   struct acpi_device *device)
1507 {
1508 	int status = 0;
1509 	struct acpi_device *dev;
1510 
1511 	/*
1512 	 * There are systems where video module known to work fine regardless
1513 	 * of broken _DOD and ignoring returned value here doesn't cause
1514 	 * any issues later.
1515 	 */
1516 	acpi_video_device_enumerate(video);
1517 
1518 	list_for_each_entry(dev, &device->children, node) {
1519 
1520 		status = acpi_video_bus_get_one_device(dev, video);
1521 		if (status) {
1522 			dev_err(&dev->dev, "Can't attach device\n");
1523 			break;
1524 		}
1525 		video->child_count++;
1526 	}
1527 	return status;
1528 }
1529 
1530 /* acpi_video interface */
1531 
1532 /*
1533  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1534  * preform any automatic brightness change on receiving a notification.
1535  */
1536 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1537 {
1538 	return acpi_video_bus_DOS(video, 0,
1539 				  acpi_osi_is_win8() ? 1 : 0);
1540 }
1541 
1542 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1543 {
1544 	return acpi_video_bus_DOS(video, 0,
1545 				  acpi_osi_is_win8() ? 0 : 1);
1546 }
1547 
1548 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1549 {
1550 	struct acpi_video_bus *video = acpi_driver_data(device);
1551 	struct input_dev *input;
1552 	int keycode = 0;
1553 
1554 	if (!video || !video->input)
1555 		return;
1556 
1557 	input = video->input;
1558 
1559 	switch (event) {
1560 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1561 					 * most likely via hotkey. */
1562 		keycode = KEY_SWITCHVIDEOMODE;
1563 		break;
1564 
1565 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1566 					 * connector. */
1567 		acpi_video_device_enumerate(video);
1568 		acpi_video_device_rebind(video);
1569 		keycode = KEY_SWITCHVIDEOMODE;
1570 		break;
1571 
1572 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1573 		keycode = KEY_SWITCHVIDEOMODE;
1574 		break;
1575 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1576 		keycode = KEY_VIDEO_NEXT;
1577 		break;
1578 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1579 		keycode = KEY_VIDEO_PREV;
1580 		break;
1581 
1582 	default:
1583 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1584 				  "Unsupported event [0x%x]\n", event));
1585 		break;
1586 	}
1587 
1588 	if (acpi_notifier_call_chain(device, event, 0))
1589 		/* Something vetoed the keypress. */
1590 		keycode = 0;
1591 
1592 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1593 		input_report_key(input, keycode, 1);
1594 		input_sync(input);
1595 		input_report_key(input, keycode, 0);
1596 		input_sync(input);
1597 	}
1598 
1599 	return;
1600 }
1601 
1602 static void brightness_switch_event(struct acpi_video_device *video_device,
1603 				    u32 event)
1604 {
1605 	if (!brightness_switch_enabled)
1606 		return;
1607 
1608 	video_device->switch_brightness_event = event;
1609 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1610 }
1611 
1612 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1613 {
1614 	struct acpi_video_device *video_device = data;
1615 	struct acpi_device *device = NULL;
1616 	struct acpi_video_bus *bus;
1617 	struct input_dev *input;
1618 	int keycode = 0;
1619 
1620 	if (!video_device)
1621 		return;
1622 
1623 	device = video_device->dev;
1624 	bus = video_device->video;
1625 	input = bus->input;
1626 
1627 	switch (event) {
1628 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1629 		brightness_switch_event(video_device, event);
1630 		keycode = KEY_BRIGHTNESS_CYCLE;
1631 		break;
1632 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1633 		brightness_switch_event(video_device, event);
1634 		keycode = KEY_BRIGHTNESSUP;
1635 		break;
1636 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1637 		brightness_switch_event(video_device, event);
1638 		keycode = KEY_BRIGHTNESSDOWN;
1639 		break;
1640 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1641 		brightness_switch_event(video_device, event);
1642 		keycode = KEY_BRIGHTNESS_ZERO;
1643 		break;
1644 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1645 		brightness_switch_event(video_device, event);
1646 		keycode = KEY_DISPLAY_OFF;
1647 		break;
1648 	default:
1649 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1650 				  "Unsupported event [0x%x]\n", event));
1651 		break;
1652 	}
1653 
1654 	acpi_notifier_call_chain(device, event, 0);
1655 
1656 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1657 		input_report_key(input, keycode, 1);
1658 		input_sync(input);
1659 		input_report_key(input, keycode, 0);
1660 		input_sync(input);
1661 	}
1662 
1663 	return;
1664 }
1665 
1666 static int acpi_video_resume(struct notifier_block *nb,
1667 				unsigned long val, void *ign)
1668 {
1669 	struct acpi_video_bus *video;
1670 	struct acpi_video_device *video_device;
1671 	int i;
1672 
1673 	switch (val) {
1674 	case PM_HIBERNATION_PREPARE:
1675 	case PM_SUSPEND_PREPARE:
1676 	case PM_RESTORE_PREPARE:
1677 		return NOTIFY_DONE;
1678 	}
1679 
1680 	video = container_of(nb, struct acpi_video_bus, pm_nb);
1681 
1682 	dev_info(&video->device->dev, "Restoring backlight state\n");
1683 
1684 	for (i = 0; i < video->attached_count; i++) {
1685 		video_device = video->attached_array[i].bind_info;
1686 		if (video_device && video_device->brightness)
1687 			acpi_video_device_lcd_set_level(video_device,
1688 					video_device->brightness->curr);
1689 	}
1690 
1691 	return NOTIFY_OK;
1692 }
1693 
1694 static acpi_status
1695 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1696 			void **return_value)
1697 {
1698 	struct acpi_device *device = context;
1699 	struct acpi_device *sibling;
1700 	int result;
1701 
1702 	if (handle == device->handle)
1703 		return AE_CTRL_TERMINATE;
1704 
1705 	result = acpi_bus_get_device(handle, &sibling);
1706 	if (result)
1707 		return AE_OK;
1708 
1709 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1710 			return AE_ALREADY_EXISTS;
1711 
1712 	return AE_OK;
1713 }
1714 
1715 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1716 {
1717 	struct backlight_properties props;
1718 	struct pci_dev *pdev;
1719 	acpi_handle acpi_parent;
1720 	struct device *parent = NULL;
1721 	int result;
1722 	static int count;
1723 	char *name;
1724 
1725 	result = acpi_video_init_brightness(device);
1726 	if (result)
1727 		return;
1728 
1729 	if (disable_backlight_sysfs_if > 0)
1730 		return;
1731 
1732 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1733 	if (!name)
1734 		return;
1735 	count++;
1736 
1737 	acpi_get_parent(device->dev->handle, &acpi_parent);
1738 
1739 	pdev = acpi_get_pci_dev(acpi_parent);
1740 	if (pdev) {
1741 		parent = &pdev->dev;
1742 		pci_dev_put(pdev);
1743 	}
1744 
1745 	memset(&props, 0, sizeof(struct backlight_properties));
1746 	props.type = BACKLIGHT_FIRMWARE;
1747 	props.max_brightness =
1748 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1749 	device->backlight = backlight_device_register(name,
1750 						      parent,
1751 						      device,
1752 						      &acpi_backlight_ops,
1753 						      &props);
1754 	kfree(name);
1755 	if (IS_ERR(device->backlight)) {
1756 		device->backlight = NULL;
1757 		return;
1758 	}
1759 
1760 	/*
1761 	 * Save current brightness level in case we have to restore it
1762 	 * before acpi_video_device_lcd_set_level() is called next time.
1763 	 */
1764 	device->backlight->props.brightness =
1765 			acpi_video_get_brightness(device->backlight);
1766 
1767 	device->cooling_dev = thermal_cooling_device_register("LCD",
1768 				device->dev, &video_cooling_ops);
1769 	if (IS_ERR(device->cooling_dev)) {
1770 		/*
1771 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1772 		 * Also, why the hell we are returning early and not attempt to
1773 		 * register video output if cooling device registration failed?
1774 		 * -- dtor
1775 		 */
1776 		device->cooling_dev = NULL;
1777 		return;
1778 	}
1779 
1780 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1781 		 device->cooling_dev->id);
1782 	result = sysfs_create_link(&device->dev->dev.kobj,
1783 			&device->cooling_dev->device.kobj,
1784 			"thermal_cooling");
1785 	if (result)
1786 		printk(KERN_ERR PREFIX "Create sysfs link\n");
1787 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1788 			&device->dev->dev.kobj, "device");
1789 	if (result)
1790 		printk(KERN_ERR PREFIX "Create sysfs link\n");
1791 }
1792 
1793 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1794 {
1795 	struct acpi_video_device *dev;
1796 	union acpi_object *levels;
1797 
1798 	mutex_lock(&video->device_list_lock);
1799 	list_for_each_entry(dev, &video->video_device_list, entry) {
1800 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1801 			kfree(levels);
1802 	}
1803 	mutex_unlock(&video->device_list_lock);
1804 }
1805 
1806 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1807 {
1808 	/*
1809 	 * Do not create backlight device for video output
1810 	 * device that is not in the enumerated list.
1811 	 */
1812 	if (!acpi_video_device_in_dod(dev)) {
1813 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1814 		return false;
1815 	}
1816 
1817 	if (only_lcd)
1818 		return dev->flags.lcd;
1819 	return true;
1820 }
1821 
1822 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1823 {
1824 	struct acpi_video_device *dev;
1825 
1826 	if (video->backlight_registered)
1827 		return 0;
1828 
1829 	acpi_video_run_bcl_for_osi(video);
1830 
1831 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1832 		return 0;
1833 
1834 	mutex_lock(&video->device_list_lock);
1835 	list_for_each_entry(dev, &video->video_device_list, entry) {
1836 		if (acpi_video_should_register_backlight(dev))
1837 			acpi_video_dev_register_backlight(dev);
1838 	}
1839 	mutex_unlock(&video->device_list_lock);
1840 
1841 	video->backlight_registered = true;
1842 
1843 	video->pm_nb.notifier_call = acpi_video_resume;
1844 	video->pm_nb.priority = 0;
1845 	return register_pm_notifier(&video->pm_nb);
1846 }
1847 
1848 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1849 {
1850 	if (device->backlight) {
1851 		backlight_device_unregister(device->backlight);
1852 		device->backlight = NULL;
1853 	}
1854 	if (device->brightness) {
1855 		kfree(device->brightness->levels);
1856 		kfree(device->brightness);
1857 		device->brightness = NULL;
1858 	}
1859 	if (device->cooling_dev) {
1860 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1861 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1862 		thermal_cooling_device_unregister(device->cooling_dev);
1863 		device->cooling_dev = NULL;
1864 	}
1865 }
1866 
1867 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1868 {
1869 	struct acpi_video_device *dev;
1870 	int error;
1871 
1872 	if (!video->backlight_registered)
1873 		return 0;
1874 
1875 	error = unregister_pm_notifier(&video->pm_nb);
1876 
1877 	mutex_lock(&video->device_list_lock);
1878 	list_for_each_entry(dev, &video->video_device_list, entry)
1879 		acpi_video_dev_unregister_backlight(dev);
1880 	mutex_unlock(&video->device_list_lock);
1881 
1882 	video->backlight_registered = false;
1883 
1884 	return error;
1885 }
1886 
1887 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1888 {
1889 	acpi_status status;
1890 	struct acpi_device *adev = device->dev;
1891 
1892 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1893 					     acpi_video_device_notify, device);
1894 	if (ACPI_FAILURE(status))
1895 		dev_err(&adev->dev, "Error installing notify handler\n");
1896 	else
1897 		device->flags.notify = 1;
1898 }
1899 
1900 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1901 {
1902 	struct input_dev *input;
1903 	struct acpi_video_device *dev;
1904 	int error;
1905 
1906 	video->input = input = input_allocate_device();
1907 	if (!input) {
1908 		error = -ENOMEM;
1909 		goto out;
1910 	}
1911 
1912 	error = acpi_video_bus_start_devices(video);
1913 	if (error)
1914 		goto err_free_input;
1915 
1916 	snprintf(video->phys, sizeof(video->phys),
1917 			"%s/video/input0", acpi_device_hid(video->device));
1918 
1919 	input->name = acpi_device_name(video->device);
1920 	input->phys = video->phys;
1921 	input->id.bustype = BUS_HOST;
1922 	input->id.product = 0x06;
1923 	input->dev.parent = &video->device->dev;
1924 	input->evbit[0] = BIT(EV_KEY);
1925 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1926 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1927 	set_bit(KEY_VIDEO_PREV, input->keybit);
1928 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1929 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1930 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1931 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1932 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1933 
1934 	error = input_register_device(input);
1935 	if (error)
1936 		goto err_stop_dev;
1937 
1938 	mutex_lock(&video->device_list_lock);
1939 	list_for_each_entry(dev, &video->video_device_list, entry)
1940 		acpi_video_dev_add_notify_handler(dev);
1941 	mutex_unlock(&video->device_list_lock);
1942 
1943 	return 0;
1944 
1945 err_stop_dev:
1946 	acpi_video_bus_stop_devices(video);
1947 err_free_input:
1948 	input_free_device(input);
1949 	video->input = NULL;
1950 out:
1951 	return error;
1952 }
1953 
1954 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1955 {
1956 	if (dev->flags.notify) {
1957 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1958 					   acpi_video_device_notify);
1959 		dev->flags.notify = 0;
1960 	}
1961 }
1962 
1963 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1964 {
1965 	struct acpi_video_device *dev;
1966 
1967 	mutex_lock(&video->device_list_lock);
1968 	list_for_each_entry(dev, &video->video_device_list, entry)
1969 		acpi_video_dev_remove_notify_handler(dev);
1970 	mutex_unlock(&video->device_list_lock);
1971 
1972 	acpi_video_bus_stop_devices(video);
1973 	input_unregister_device(video->input);
1974 	video->input = NULL;
1975 }
1976 
1977 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1978 {
1979 	struct acpi_video_device *dev, *next;
1980 
1981 	mutex_lock(&video->device_list_lock);
1982 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1983 		list_del(&dev->entry);
1984 		kfree(dev);
1985 	}
1986 	mutex_unlock(&video->device_list_lock);
1987 
1988 	return 0;
1989 }
1990 
1991 static int instance;
1992 
1993 static int acpi_video_bus_add(struct acpi_device *device)
1994 {
1995 	struct acpi_video_bus *video;
1996 	int error;
1997 	acpi_status status;
1998 
1999 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
2000 				device->parent->handle, 1,
2001 				acpi_video_bus_match, NULL,
2002 				device, NULL);
2003 	if (status == AE_ALREADY_EXISTS) {
2004 		printk(KERN_WARNING FW_BUG
2005 			"Duplicate ACPI video bus devices for the"
2006 			" same VGA controller, please try module "
2007 			"parameter \"video.allow_duplicates=1\""
2008 			"if the current driver doesn't work.\n");
2009 		if (!allow_duplicates)
2010 			return -ENODEV;
2011 	}
2012 
2013 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2014 	if (!video)
2015 		return -ENOMEM;
2016 
2017 	/* a hack to fix the duplicate name "VID" problem on T61 */
2018 	if (!strcmp(device->pnp.bus_id, "VID")) {
2019 		if (instance)
2020 			device->pnp.bus_id[3] = '0' + instance;
2021 		instance++;
2022 	}
2023 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2024 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2025 		if (instance)
2026 			device->pnp.bus_id[3] = '0' + instance;
2027 		instance++;
2028 	}
2029 
2030 	video->device = device;
2031 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2032 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2033 	device->driver_data = video;
2034 
2035 	acpi_video_bus_find_cap(video);
2036 	error = acpi_video_bus_check(video);
2037 	if (error)
2038 		goto err_free_video;
2039 
2040 	mutex_init(&video->device_list_lock);
2041 	INIT_LIST_HEAD(&video->video_device_list);
2042 
2043 	error = acpi_video_bus_get_devices(video, device);
2044 	if (error)
2045 		goto err_put_video;
2046 
2047 	printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2048 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2049 	       video->flags.multihead ? "yes" : "no",
2050 	       video->flags.rom ? "yes" : "no",
2051 	       video->flags.post ? "yes" : "no");
2052 	mutex_lock(&video_list_lock);
2053 	list_add_tail(&video->entry, &video_bus_head);
2054 	mutex_unlock(&video_list_lock);
2055 
2056 	acpi_video_bus_register_backlight(video);
2057 	acpi_video_bus_add_notify_handler(video);
2058 
2059 	return 0;
2060 
2061 err_put_video:
2062 	acpi_video_bus_put_devices(video);
2063 	kfree(video->attached_array);
2064 err_free_video:
2065 	kfree(video);
2066 	device->driver_data = NULL;
2067 
2068 	return error;
2069 }
2070 
2071 static int acpi_video_bus_remove(struct acpi_device *device)
2072 {
2073 	struct acpi_video_bus *video = NULL;
2074 
2075 
2076 	if (!device || !acpi_driver_data(device))
2077 		return -EINVAL;
2078 
2079 	video = acpi_driver_data(device);
2080 
2081 	acpi_video_bus_remove_notify_handler(video);
2082 	acpi_video_bus_unregister_backlight(video);
2083 	acpi_video_bus_put_devices(video);
2084 
2085 	mutex_lock(&video_list_lock);
2086 	list_del(&video->entry);
2087 	mutex_unlock(&video_list_lock);
2088 
2089 	kfree(video->attached_array);
2090 	kfree(video);
2091 
2092 	return 0;
2093 }
2094 
2095 static int __init is_i740(struct pci_dev *dev)
2096 {
2097 	if (dev->device == 0x00D1)
2098 		return 1;
2099 	if (dev->device == 0x7000)
2100 		return 1;
2101 	return 0;
2102 }
2103 
2104 static int __init intel_opregion_present(void)
2105 {
2106 	int opregion = 0;
2107 	struct pci_dev *dev = NULL;
2108 	u32 address;
2109 
2110 	for_each_pci_dev(dev) {
2111 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2112 			continue;
2113 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2114 			continue;
2115 		/* We don't want to poke around undefined i740 registers */
2116 		if (is_i740(dev))
2117 			continue;
2118 		pci_read_config_dword(dev, 0xfc, &address);
2119 		if (!address)
2120 			continue;
2121 		opregion = 1;
2122 	}
2123 	return opregion;
2124 }
2125 
2126 int acpi_video_register(void)
2127 {
2128 	int ret = 0;
2129 
2130 	mutex_lock(&register_count_mutex);
2131 	if (register_count) {
2132 		/*
2133 		 * if the function of acpi_video_register is already called,
2134 		 * don't register the acpi_vide_bus again and return no error.
2135 		 */
2136 		goto leave;
2137 	}
2138 
2139 	dmi_check_system(video_dmi_table);
2140 
2141 	ret = acpi_bus_register_driver(&acpi_video_bus);
2142 	if (ret)
2143 		goto leave;
2144 
2145 	/*
2146 	 * When the acpi_video_bus is loaded successfully, increase
2147 	 * the counter reference.
2148 	 */
2149 	register_count = 1;
2150 
2151 leave:
2152 	mutex_unlock(&register_count_mutex);
2153 	return ret;
2154 }
2155 EXPORT_SYMBOL(acpi_video_register);
2156 
2157 void acpi_video_unregister(void)
2158 {
2159 	mutex_lock(&register_count_mutex);
2160 	if (register_count) {
2161 		acpi_bus_unregister_driver(&acpi_video_bus);
2162 		register_count = 0;
2163 	}
2164 	mutex_unlock(&register_count_mutex);
2165 }
2166 EXPORT_SYMBOL(acpi_video_unregister);
2167 
2168 void acpi_video_unregister_backlight(void)
2169 {
2170 	struct acpi_video_bus *video;
2171 
2172 	mutex_lock(&register_count_mutex);
2173 	if (register_count) {
2174 		mutex_lock(&video_list_lock);
2175 		list_for_each_entry(video, &video_bus_head, entry)
2176 			acpi_video_bus_unregister_backlight(video);
2177 		mutex_unlock(&video_list_lock);
2178 	}
2179 	mutex_unlock(&register_count_mutex);
2180 }
2181 
2182 bool acpi_video_handles_brightness_key_presses(void)
2183 {
2184 	bool have_video_busses;
2185 
2186 	mutex_lock(&video_list_lock);
2187 	have_video_busses = !list_empty(&video_bus_head);
2188 	mutex_unlock(&video_list_lock);
2189 
2190 	return have_video_busses &&
2191 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2192 }
2193 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2194 
2195 /*
2196  * This is kind of nasty. Hardware using Intel chipsets may require
2197  * the video opregion code to be run first in order to initialise
2198  * state before any ACPI video calls are made. To handle this we defer
2199  * registration of the video class until the opregion code has run.
2200  */
2201 
2202 static int __init acpi_video_init(void)
2203 {
2204 	/*
2205 	 * Let the module load even if ACPI is disabled (e.g. due to
2206 	 * a broken BIOS) so that i915.ko can still be loaded on such
2207 	 * old systems without an AcpiOpRegion.
2208 	 *
2209 	 * acpi_video_register() will report -ENODEV later as well due
2210 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2211 	 */
2212 	if (acpi_disabled)
2213 		return 0;
2214 
2215 	if (intel_opregion_present())
2216 		return 0;
2217 
2218 	return acpi_video_register();
2219 }
2220 
2221 static void __exit acpi_video_exit(void)
2222 {
2223 	acpi_video_detect_exit();
2224 	acpi_video_unregister();
2225 
2226 	return;
2227 }
2228 
2229 module_init(acpi_video_init);
2230 module_exit(acpi_video_exit);
2231