xref: /openbmc/linux/drivers/acpi/acpi_video.c (revision 22d55f02)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  video.c - ACPI Video Driver
4  *
5  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
6  *  Copyright (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
7  *  Copyright (C) 2006 Thomas Tuttle <linux-kernel@ttuttle.net>
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/types.h>
14 #include <linux/list.h>
15 #include <linux/mutex.h>
16 #include <linux/input.h>
17 #include <linux/backlight.h>
18 #include <linux/thermal.h>
19 #include <linux/sort.h>
20 #include <linux/pci.h>
21 #include <linux/pci_ids.h>
22 #include <linux/slab.h>
23 #include <linux/dmi.h>
24 #include <linux/suspend.h>
25 #include <linux/acpi.h>
26 #include <acpi/video.h>
27 #include <linux/uaccess.h>
28 
29 #define PREFIX "ACPI: "
30 
31 #define ACPI_VIDEO_BUS_NAME		"Video Bus"
32 #define ACPI_VIDEO_DEVICE_NAME		"Video Device"
33 
34 #define MAX_NAME_LEN	20
35 
36 #define _COMPONENT		ACPI_VIDEO_COMPONENT
37 ACPI_MODULE_NAME("video");
38 
39 MODULE_AUTHOR("Bruno Ducrot");
40 MODULE_DESCRIPTION("ACPI Video Driver");
41 MODULE_LICENSE("GPL");
42 
43 static bool brightness_switch_enabled = true;
44 module_param(brightness_switch_enabled, bool, 0644);
45 
46 /*
47  * By default, we don't allow duplicate ACPI video bus devices
48  * under the same VGA controller
49  */
50 static bool allow_duplicates;
51 module_param(allow_duplicates, bool, 0644);
52 
53 static int disable_backlight_sysfs_if = -1;
54 module_param(disable_backlight_sysfs_if, int, 0444);
55 
56 #define REPORT_OUTPUT_KEY_EVENTS		0x01
57 #define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
58 static int report_key_events = -1;
59 module_param(report_key_events, int, 0644);
60 MODULE_PARM_DESC(report_key_events,
61 	"0: none, 1: output changes, 2: brightness changes, 3: all");
62 
63 /*
64  * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be
65  * assumed even if not actually set.
66  */
67 static bool device_id_scheme = false;
68 module_param(device_id_scheme, bool, 0444);
69 
70 static int only_lcd = -1;
71 module_param(only_lcd, int, 0444);
72 
73 static int register_count;
74 static DEFINE_MUTEX(register_count_mutex);
75 static DEFINE_MUTEX(video_list_lock);
76 static LIST_HEAD(video_bus_head);
77 static int acpi_video_bus_add(struct acpi_device *device);
78 static int acpi_video_bus_remove(struct acpi_device *device);
79 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
80 void acpi_video_detect_exit(void);
81 
82 /*
83  * Indices in the _BCL method response: the first two items are special,
84  * the rest are all supported levels.
85  *
86  * See page 575 of the ACPI spec 3.0
87  */
88 enum acpi_video_level_idx {
89 	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
90 	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
91 	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
92 };
93 
94 static const struct acpi_device_id video_device_ids[] = {
95 	{ACPI_VIDEO_HID, 0},
96 	{"", 0},
97 };
98 MODULE_DEVICE_TABLE(acpi, video_device_ids);
99 
100 static struct acpi_driver acpi_video_bus = {
101 	.name = "video",
102 	.class = ACPI_VIDEO_CLASS,
103 	.ids = video_device_ids,
104 	.ops = {
105 		.add = acpi_video_bus_add,
106 		.remove = acpi_video_bus_remove,
107 		.notify = acpi_video_bus_notify,
108 		},
109 };
110 
111 struct acpi_video_bus_flags {
112 	u8 multihead:1;		/* can switch video heads */
113 	u8 rom:1;		/* can retrieve a video rom */
114 	u8 post:1;		/* can configure the head to */
115 	u8 reserved:5;
116 };
117 
118 struct acpi_video_bus_cap {
119 	u8 _DOS:1;		/* Enable/Disable output switching */
120 	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
121 	u8 _ROM:1;		/* Get ROM Data */
122 	u8 _GPD:1;		/* Get POST Device */
123 	u8 _SPD:1;		/* Set POST Device */
124 	u8 _VPO:1;		/* Video POST Options */
125 	u8 reserved:2;
126 };
127 
128 struct acpi_video_device_attrib {
129 	u32 display_index:4;	/* A zero-based instance of the Display */
130 	u32 display_port_attachment:4;	/* This field differentiates the display type */
131 	u32 display_type:4;	/* Describe the specific type in use */
132 	u32 vendor_specific:4;	/* Chipset Vendor Specific */
133 	u32 bios_can_detect:1;	/* BIOS can detect the device */
134 	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
135 				   the VGA device. */
136 	u32 pipe_id:3;		/* For VGA multiple-head devices. */
137 	u32 reserved:10;	/* Must be 0 */
138 
139 	/*
140 	 * The device ID might not actually follow the scheme described by this
141 	 * struct acpi_video_device_attrib. If it does, then this bit
142 	 * device_id_scheme is set; otherwise, other fields should be ignored.
143 	 *
144 	 * (but also see the global flag device_id_scheme)
145 	 */
146 	u32 device_id_scheme:1;
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 = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
232 		if (vd->brightness->levels[i] == cur_level)
233 			return i - ACPI_VIDEO_FIRST_LEVEL;
234 	}
235 	return 0;
236 }
237 
238 static int acpi_video_set_brightness(struct backlight_device *bd)
239 {
240 	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
241 	struct acpi_video_device *vd = bl_get_data(bd);
242 
243 	cancel_delayed_work(&vd->switch_brightness_work);
244 	return acpi_video_device_lcd_set_level(vd,
245 				vd->brightness->levels[request_level]);
246 }
247 
248 static const struct backlight_ops acpi_backlight_ops = {
249 	.get_brightness = acpi_video_get_brightness,
250 	.update_status  = acpi_video_set_brightness,
251 };
252 
253 /* thermal cooling device callbacks */
254 static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
255 			       unsigned long *state)
256 {
257 	struct acpi_device *device = cooling_dev->devdata;
258 	struct acpi_video_device *video = acpi_driver_data(device);
259 
260 	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
261 	return 0;
262 }
263 
264 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
265 			       unsigned long *state)
266 {
267 	struct acpi_device *device = cooling_dev->devdata;
268 	struct acpi_video_device *video = acpi_driver_data(device);
269 	unsigned long long level;
270 	int offset;
271 
272 	if (acpi_video_device_lcd_get_level_current(video, &level, false))
273 		return -EINVAL;
274 	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
275 	     offset++)
276 		if (level == video->brightness->levels[offset]) {
277 			*state = video->brightness->count - offset - 1;
278 			return 0;
279 		}
280 
281 	return -EINVAL;
282 }
283 
284 static int
285 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
286 {
287 	struct acpi_device *device = cooling_dev->devdata;
288 	struct acpi_video_device *video = acpi_driver_data(device);
289 	int level;
290 
291 	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
292 		return -EINVAL;
293 
294 	state = video->brightness->count - state;
295 	level = video->brightness->levels[state - 1];
296 	return acpi_video_device_lcd_set_level(video, level);
297 }
298 
299 static const struct thermal_cooling_device_ops video_cooling_ops = {
300 	.get_max_state = video_get_max_state,
301 	.get_cur_state = video_get_cur_state,
302 	.set_cur_state = video_set_cur_state,
303 };
304 
305 /*
306  * --------------------------------------------------------------------------
307  *                             Video Management
308  * --------------------------------------------------------------------------
309  */
310 
311 static int
312 acpi_video_device_lcd_query_levels(acpi_handle handle,
313 				   union acpi_object **levels)
314 {
315 	int status;
316 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
317 	union acpi_object *obj;
318 
319 
320 	*levels = NULL;
321 
322 	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
323 	if (!ACPI_SUCCESS(status))
324 		return status;
325 	obj = (union acpi_object *)buffer.pointer;
326 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
327 		printk(KERN_ERR PREFIX "Invalid _BCL data\n");
328 		status = -EFAULT;
329 		goto err;
330 	}
331 
332 	*levels = obj;
333 
334 	return 0;
335 
336 err:
337 	kfree(buffer.pointer);
338 
339 	return status;
340 }
341 
342 static int
343 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
344 {
345 	int status;
346 	int state;
347 
348 	status = acpi_execute_simple_method(device->dev->handle,
349 					    "_BCM", level);
350 	if (ACPI_FAILURE(status)) {
351 		ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
352 		return -EIO;
353 	}
354 
355 	device->brightness->curr = level;
356 	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
357 	     state++)
358 		if (level == device->brightness->levels[state]) {
359 			if (device->backlight)
360 				device->backlight->props.brightness =
361 					state - ACPI_VIDEO_FIRST_LEVEL;
362 			return 0;
363 		}
364 
365 	ACPI_ERROR((AE_INFO, "Current brightness invalid"));
366 	return -EINVAL;
367 }
368 
369 /*
370  * For some buggy _BQC methods, we need to add a constant value to
371  * the _BQC return value to get the actual current brightness level
372  */
373 
374 static int bqc_offset_aml_bug_workaround;
375 static int video_set_bqc_offset(const struct dmi_system_id *d)
376 {
377 	bqc_offset_aml_bug_workaround = 9;
378 	return 0;
379 }
380 
381 static int video_disable_backlight_sysfs_if(
382 	const struct dmi_system_id *d)
383 {
384 	if (disable_backlight_sysfs_if == -1)
385 		disable_backlight_sysfs_if = 1;
386 	return 0;
387 }
388 
389 static int video_set_device_id_scheme(const struct dmi_system_id *d)
390 {
391 	device_id_scheme = true;
392 	return 0;
393 }
394 
395 static int video_enable_only_lcd(const struct dmi_system_id *d)
396 {
397 	only_lcd = true;
398 	return 0;
399 }
400 
401 static int video_set_report_key_events(const struct dmi_system_id *id)
402 {
403 	if (report_key_events == -1)
404 		report_key_events = (uintptr_t)id->driver_data;
405 	return 0;
406 }
407 
408 static const struct dmi_system_id video_dmi_table[] = {
409 	/*
410 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
411 	 */
412 	{
413 	 .callback = video_set_bqc_offset,
414 	 .ident = "Acer Aspire 5720",
415 	 .matches = {
416 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
417 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
418 		},
419 	},
420 	{
421 	 .callback = video_set_bqc_offset,
422 	 .ident = "Acer Aspire 5710Z",
423 	 .matches = {
424 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
425 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
426 		},
427 	},
428 	{
429 	 .callback = video_set_bqc_offset,
430 	 .ident = "eMachines E510",
431 	 .matches = {
432 		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
433 		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
434 		},
435 	},
436 	{
437 	 .callback = video_set_bqc_offset,
438 	 .ident = "Acer Aspire 5315",
439 	 .matches = {
440 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
441 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
442 		},
443 	},
444 	{
445 	 .callback = video_set_bqc_offset,
446 	 .ident = "Acer Aspire 7720",
447 	 .matches = {
448 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
449 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
450 		},
451 	},
452 
453 	/*
454 	 * Some machines have a broken acpi-video interface for brightness
455 	 * control, but still need an acpi_video_device_lcd_set_level() call
456 	 * on resume to turn the backlight power on.  We Enable backlight
457 	 * control on these systems, but do not register a backlight sysfs
458 	 * as brightness control does not work.
459 	 */
460 	{
461 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
462 	 .callback = video_disable_backlight_sysfs_if,
463 	 .ident = "Toshiba Portege R700",
464 	 .matches = {
465 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
466 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
467 		},
468 	},
469 	{
470 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
471 	 .callback = video_disable_backlight_sysfs_if,
472 	 .ident = "Toshiba Portege R830",
473 	 .matches = {
474 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
475 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
476 		},
477 	},
478 	{
479 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
480 	 .callback = video_disable_backlight_sysfs_if,
481 	 .ident = "Toshiba Satellite R830",
482 	 .matches = {
483 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
484 		DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
485 		},
486 	},
487 	/*
488 	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
489 	 * but the IDs actually follow the Device ID Scheme.
490 	 */
491 	{
492 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
493 	 .callback = video_set_device_id_scheme,
494 	 .ident = "ESPRIMO Mobile M9410",
495 	 .matches = {
496 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
497 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
498 		},
499 	},
500 	/*
501 	 * Some machines have multiple video output devices, but only the one
502 	 * that is the type of LCD can do the backlight control so we should not
503 	 * register backlight interface for other video output devices.
504 	 */
505 	{
506 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
507 	 .callback = video_enable_only_lcd,
508 	 .ident = "ESPRIMO Mobile M9410",
509 	 .matches = {
510 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
511 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
512 		},
513 	},
514 	/*
515 	 * Some machines report wrong key events on the acpi-bus, suppress
516 	 * key event reporting on these.  Note this is only intended to work
517 	 * around events which are plain wrong. In some cases we get double
518 	 * events, in this case acpi-video is considered the canonical source
519 	 * and the events from the other source should be filtered. E.g.
520 	 * by calling acpi_video_handles_brightness_key_presses() from the
521 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
522 	 */
523 	{
524 	 .callback = video_set_report_key_events,
525 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
526 	 .ident = "Dell Vostro V131",
527 	 .matches = {
528 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
529 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
530 		},
531 	},
532 	{}
533 };
534 
535 static unsigned long long
536 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
537 			      unsigned long long bqc_value)
538 {
539 	unsigned long long level;
540 
541 	if (device->brightness->flags._BQC_use_index) {
542 		/*
543 		 * _BQC returns an index that doesn't account for the first 2
544 		 * items with special meaning (see enum acpi_video_level_idx),
545 		 * so we need to compensate for that by offsetting ourselves
546 		 */
547 		if (device->brightness->flags._BCL_reversed)
548 			bqc_value = device->brightness->count -
549 				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
550 
551 		level = device->brightness->levels[bqc_value +
552 		                                   ACPI_VIDEO_FIRST_LEVEL];
553 	} else {
554 		level = bqc_value;
555 	}
556 
557 	level += bqc_offset_aml_bug_workaround;
558 
559 	return level;
560 }
561 
562 static int
563 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
564 					unsigned long long *level, bool raw)
565 {
566 	acpi_status status = AE_OK;
567 	int i;
568 
569 	if (device->cap._BQC || device->cap._BCQ) {
570 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
571 
572 		status = acpi_evaluate_integer(device->dev->handle, buf,
573 						NULL, level);
574 		if (ACPI_SUCCESS(status)) {
575 			if (raw) {
576 				/*
577 				 * Caller has indicated he wants the raw
578 				 * value returned by _BQC, so don't furtherly
579 				 * mess with the value.
580 				 */
581 				return 0;
582 			}
583 
584 			*level = acpi_video_bqc_value_to_level(device, *level);
585 
586 			for (i = ACPI_VIDEO_FIRST_LEVEL;
587 			     i < device->brightness->count; i++)
588 				if (device->brightness->levels[i] == *level) {
589 					device->brightness->curr = *level;
590 					return 0;
591 				}
592 			/*
593 			 * BQC returned an invalid level.
594 			 * Stop using it.
595 			 */
596 			ACPI_WARNING((AE_INFO,
597 				      "%s returned an invalid level",
598 				      buf));
599 			device->cap._BQC = device->cap._BCQ = 0;
600 		} else {
601 			/*
602 			 * Fixme:
603 			 * should we return an error or ignore this failure?
604 			 * dev->brightness->curr is a cached value which stores
605 			 * the correct current backlight level in most cases.
606 			 * ACPI video backlight still works w/ buggy _BQC.
607 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
608 			 */
609 			ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
610 			device->cap._BQC = device->cap._BCQ = 0;
611 		}
612 	}
613 
614 	*level = device->brightness->curr;
615 	return 0;
616 }
617 
618 static int
619 acpi_video_device_EDID(struct acpi_video_device *device,
620 		       union acpi_object **edid, ssize_t length)
621 {
622 	int status;
623 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
624 	union acpi_object *obj;
625 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
626 	struct acpi_object_list args = { 1, &arg0 };
627 
628 
629 	*edid = NULL;
630 
631 	if (!device)
632 		return -ENODEV;
633 	if (length == 128)
634 		arg0.integer.value = 1;
635 	else if (length == 256)
636 		arg0.integer.value = 2;
637 	else
638 		return -EINVAL;
639 
640 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
641 	if (ACPI_FAILURE(status))
642 		return -ENODEV;
643 
644 	obj = buffer.pointer;
645 
646 	if (obj && obj->type == ACPI_TYPE_BUFFER)
647 		*edid = obj;
648 	else {
649 		printk(KERN_ERR PREFIX "Invalid _DDC data\n");
650 		status = -EFAULT;
651 		kfree(obj);
652 	}
653 
654 	return status;
655 }
656 
657 /* bus */
658 
659 /*
660  *  Arg:
661  *	video		: video bus device pointer
662  *	bios_flag	:
663  *		0.	The system BIOS should NOT automatically switch(toggle)
664  *			the active display output.
665  *		1.	The system BIOS should automatically switch (toggle) the
666  *			active display output. No switch event.
667  *		2.	The _DGS value should be locked.
668  *		3.	The system BIOS should not automatically switch (toggle) the
669  *			active display output, but instead generate the display switch
670  *			event notify code.
671  *	lcd_flag	:
672  *		0.	The system BIOS should automatically control the brightness level
673  *			of the LCD when the power changes from AC to DC
674  *		1.	The system BIOS should NOT automatically control the brightness
675  *			level of the LCD when the power changes from AC to DC.
676  *  Return Value:
677  *		-EINVAL	wrong arg.
678  */
679 
680 static int
681 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
682 {
683 	acpi_status status;
684 
685 	if (!video->cap._DOS)
686 		return 0;
687 
688 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
689 		return -EINVAL;
690 	video->dos_setting = (lcd_flag << 2) | bios_flag;
691 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
692 					    (lcd_flag << 2) | bios_flag);
693 	if (ACPI_FAILURE(status))
694 		return -EIO;
695 
696 	return 0;
697 }
698 
699 /*
700  * Simple comparison function used to sort backlight levels.
701  */
702 
703 static int
704 acpi_video_cmp_level(const void *a, const void *b)
705 {
706 	return *(int *)a - *(int *)b;
707 }
708 
709 /*
710  * Decides if _BQC/_BCQ for this system is usable
711  *
712  * We do this by changing the level first and then read out the current
713  * brightness level, if the value does not match, find out if it is using
714  * index. If not, clear the _BQC/_BCQ capability.
715  */
716 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
717 				int max_level, int current_level)
718 {
719 	struct acpi_video_device_brightness *br = device->brightness;
720 	int result;
721 	unsigned long long level;
722 	int test_level;
723 
724 	/* don't mess with existing known broken systems */
725 	if (bqc_offset_aml_bug_workaround)
726 		return 0;
727 
728 	/*
729 	 * Some systems always report current brightness level as maximum
730 	 * through _BQC, we need to test another value for them. However,
731 	 * there is a subtlety:
732 	 *
733 	 * If the _BCL package ordering is descending, the first level
734 	 * (br->levels[2]) is likely to be 0, and if the number of levels
735 	 * matches the number of steps, we might confuse a returned level to
736 	 * mean the index.
737 	 *
738 	 * For example:
739 	 *
740 	 *     current_level = max_level = 100
741 	 *     test_level = 0
742 	 *     returned level = 100
743 	 *
744 	 * In this case 100 means the level, not the index, and _BCM failed.
745 	 * Still, if the _BCL package ordering is descending, the index of
746 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
747 	 *
748 	 * This causes all _BQC calls to return bogus values causing weird
749 	 * behavior from the user's perspective.  For example:
750 	 *
751 	 * xbacklight -set 10; xbacklight -set 20;
752 	 *
753 	 * would flash to 90% and then slowly down to the desired level (20).
754 	 *
755 	 * The solution is simple; test anything other than the first level
756 	 * (e.g. 1).
757 	 */
758 	test_level = current_level == max_level
759 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
760 		: max_level;
761 
762 	result = acpi_video_device_lcd_set_level(device, test_level);
763 	if (result)
764 		return result;
765 
766 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
767 	if (result)
768 		return result;
769 
770 	if (level != test_level) {
771 		/* buggy _BQC found, need to find out if it uses index */
772 		if (level < br->count) {
773 			if (br->flags._BCL_reversed)
774 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
775 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
776 				br->flags._BQC_use_index = 1;
777 		}
778 
779 		if (!br->flags._BQC_use_index)
780 			device->cap._BQC = device->cap._BCQ = 0;
781 	}
782 
783 	return 0;
784 }
785 
786 int acpi_video_get_levels(struct acpi_device *device,
787 			  struct acpi_video_device_brightness **dev_br,
788 			  int *pmax_level)
789 {
790 	union acpi_object *obj = NULL;
791 	int i, max_level = 0, count = 0, level_ac_battery = 0;
792 	union acpi_object *o;
793 	struct acpi_video_device_brightness *br = NULL;
794 	int result = 0;
795 	u32 value;
796 
797 	if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device->handle,
798 								&obj))) {
799 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
800 						"LCD brightness level\n"));
801 		result = -ENODEV;
802 		goto out;
803 	}
804 
805 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
806 		result = -EINVAL;
807 		goto out;
808 	}
809 
810 	br = kzalloc(sizeof(*br), GFP_KERNEL);
811 	if (!br) {
812 		printk(KERN_ERR "can't allocate memory\n");
813 		result = -ENOMEM;
814 		goto out;
815 	}
816 
817 	/*
818 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
819 	 * in order to account for buggy BIOS which don't export the first two
820 	 * special levels (see below)
821 	 */
822 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
823 				   sizeof(*br->levels),
824 				   GFP_KERNEL);
825 	if (!br->levels) {
826 		result = -ENOMEM;
827 		goto out_free;
828 	}
829 
830 	for (i = 0; i < obj->package.count; i++) {
831 		o = (union acpi_object *)&obj->package.elements[i];
832 		if (o->type != ACPI_TYPE_INTEGER) {
833 			printk(KERN_ERR PREFIX "Invalid data\n");
834 			continue;
835 		}
836 		value = (u32) o->integer.value;
837 		/* Skip duplicate entries */
838 		if (count > ACPI_VIDEO_FIRST_LEVEL
839 		    && br->levels[count - 1] == value)
840 			continue;
841 
842 		br->levels[count] = value;
843 
844 		if (br->levels[count] > max_level)
845 			max_level = br->levels[count];
846 		count++;
847 	}
848 
849 	/*
850 	 * some buggy BIOS don't export the levels
851 	 * when machine is on AC/Battery in _BCL package.
852 	 * In this case, the first two elements in _BCL packages
853 	 * are also supported brightness levels that OS should take care of.
854 	 */
855 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
856 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
857 			level_ac_battery++;
858 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
859 			level_ac_battery++;
860 	}
861 
862 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
863 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
864 		br->flags._BCL_no_ac_battery_levels = 1;
865 		for (i = (count - 1 + level_ac_battery);
866 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
867 			br->levels[i] = br->levels[i - level_ac_battery];
868 		count += level_ac_battery;
869 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
870 		ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
871 
872 	/* Check if the _BCL package is in a reversed order */
873 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
874 		br->flags._BCL_reversed = 1;
875 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
876 		     count - ACPI_VIDEO_FIRST_LEVEL,
877 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
878 		     acpi_video_cmp_level, NULL);
879 	} else if (max_level != br->levels[count - 1])
880 		ACPI_ERROR((AE_INFO,
881 			    "Found unordered _BCL package"));
882 
883 	br->count = count;
884 	*dev_br = br;
885 	if (pmax_level)
886 		*pmax_level = max_level;
887 
888 out:
889 	kfree(obj);
890 	return result;
891 out_free:
892 	kfree(br);
893 	goto out;
894 }
895 EXPORT_SYMBOL(acpi_video_get_levels);
896 
897 /*
898  *  Arg:
899  *	device	: video output device (LCD, CRT, ..)
900  *
901  *  Return Value:
902  *	Maximum brightness level
903  *
904  *  Allocate and initialize device->brightness.
905  */
906 
907 static int
908 acpi_video_init_brightness(struct acpi_video_device *device)
909 {
910 	int i, max_level = 0;
911 	unsigned long long level, level_old;
912 	struct acpi_video_device_brightness *br = NULL;
913 	int result = -EINVAL;
914 
915 	result = acpi_video_get_levels(device->dev, &br, &max_level);
916 	if (result)
917 		return result;
918 	device->brightness = br;
919 
920 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
921 	br->curr = level = max_level;
922 
923 	if (!device->cap._BQC)
924 		goto set_level;
925 
926 	result = acpi_video_device_lcd_get_level_current(device,
927 							 &level_old, true);
928 	if (result)
929 		goto out_free_levels;
930 
931 	result = acpi_video_bqc_quirk(device, max_level, level_old);
932 	if (result)
933 		goto out_free_levels;
934 	/*
935 	 * cap._BQC may get cleared due to _BQC is found to be broken
936 	 * in acpi_video_bqc_quirk, so check again here.
937 	 */
938 	if (!device->cap._BQC)
939 		goto set_level;
940 
941 	level = acpi_video_bqc_value_to_level(device, level_old);
942 	/*
943 	 * On some buggy laptops, _BQC returns an uninitialized
944 	 * value when invoked for the first time, i.e.
945 	 * level_old is invalid (no matter whether it's a level
946 	 * or an index). Set the backlight to max_level in this case.
947 	 */
948 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
949 		if (level == br->levels[i])
950 			break;
951 	if (i == br->count || !level)
952 		level = max_level;
953 
954 set_level:
955 	result = acpi_video_device_lcd_set_level(device, level);
956 	if (result)
957 		goto out_free_levels;
958 
959 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
960 	                  "found %d brightness levels\n",
961 	                  br->count - ACPI_VIDEO_FIRST_LEVEL));
962 	return 0;
963 
964 out_free_levels:
965 	kfree(br->levels);
966 	kfree(br);
967 	device->brightness = NULL;
968 	return result;
969 }
970 
971 /*
972  *  Arg:
973  *	device	: video output device (LCD, CRT, ..)
974  *
975  *  Return Value:
976  *	None
977  *
978  *  Find out all required AML methods defined under the output
979  *  device.
980  */
981 
982 static void acpi_video_device_find_cap(struct acpi_video_device *device)
983 {
984 	if (acpi_has_method(device->dev->handle, "_ADR"))
985 		device->cap._ADR = 1;
986 	if (acpi_has_method(device->dev->handle, "_BCL"))
987 		device->cap._BCL = 1;
988 	if (acpi_has_method(device->dev->handle, "_BCM"))
989 		device->cap._BCM = 1;
990 	if (acpi_has_method(device->dev->handle, "_BQC")) {
991 		device->cap._BQC = 1;
992 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
993 		printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
994 		device->cap._BCQ = 1;
995 	}
996 
997 	if (acpi_has_method(device->dev->handle, "_DDC"))
998 		device->cap._DDC = 1;
999 }
1000 
1001 /*
1002  *  Arg:
1003  *	device	: video output device (VGA)
1004  *
1005  *  Return Value:
1006  *	None
1007  *
1008  *  Find out all required AML methods defined under the video bus device.
1009  */
1010 
1011 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1012 {
1013 	if (acpi_has_method(video->device->handle, "_DOS"))
1014 		video->cap._DOS = 1;
1015 	if (acpi_has_method(video->device->handle, "_DOD"))
1016 		video->cap._DOD = 1;
1017 	if (acpi_has_method(video->device->handle, "_ROM"))
1018 		video->cap._ROM = 1;
1019 	if (acpi_has_method(video->device->handle, "_GPD"))
1020 		video->cap._GPD = 1;
1021 	if (acpi_has_method(video->device->handle, "_SPD"))
1022 		video->cap._SPD = 1;
1023 	if (acpi_has_method(video->device->handle, "_VPO"))
1024 		video->cap._VPO = 1;
1025 }
1026 
1027 /*
1028  * Check whether the video bus device has required AML method to
1029  * support the desired features
1030  */
1031 
1032 static int acpi_video_bus_check(struct acpi_video_bus *video)
1033 {
1034 	acpi_status status = -ENOENT;
1035 	struct pci_dev *dev;
1036 
1037 	if (!video)
1038 		return -EINVAL;
1039 
1040 	dev = acpi_get_pci_dev(video->device->handle);
1041 	if (!dev)
1042 		return -ENODEV;
1043 	pci_dev_put(dev);
1044 
1045 	/*
1046 	 * Since there is no HID, CID and so on for VGA driver, we have
1047 	 * to check well known required nodes.
1048 	 */
1049 
1050 	/* Does this device support video switching? */
1051 	if (video->cap._DOS || video->cap._DOD) {
1052 		if (!video->cap._DOS) {
1053 			printk(KERN_WARNING FW_BUG
1054 				"ACPI(%s) defines _DOD but not _DOS\n",
1055 				acpi_device_bid(video->device));
1056 		}
1057 		video->flags.multihead = 1;
1058 		status = 0;
1059 	}
1060 
1061 	/* Does this device support retrieving a video ROM? */
1062 	if (video->cap._ROM) {
1063 		video->flags.rom = 1;
1064 		status = 0;
1065 	}
1066 
1067 	/* Does this device support configuring which video device to POST? */
1068 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1069 		video->flags.post = 1;
1070 		status = 0;
1071 	}
1072 
1073 	return status;
1074 }
1075 
1076 /*
1077  * --------------------------------------------------------------------------
1078  *                               Driver Interface
1079  * --------------------------------------------------------------------------
1080  */
1081 
1082 /* device interface */
1083 static struct acpi_video_device_attrib *
1084 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1085 {
1086 	struct acpi_video_enumerated_device *ids;
1087 	int i;
1088 
1089 	for (i = 0; i < video->attached_count; i++) {
1090 		ids = &video->attached_array[i];
1091 		if ((ids->value.int_val & 0xffff) == device_id)
1092 			return &ids->value.attrib;
1093 	}
1094 
1095 	return NULL;
1096 }
1097 
1098 static int
1099 acpi_video_get_device_type(struct acpi_video_bus *video,
1100 			   unsigned long device_id)
1101 {
1102 	struct acpi_video_enumerated_device *ids;
1103 	int i;
1104 
1105 	for (i = 0; i < video->attached_count; i++) {
1106 		ids = &video->attached_array[i];
1107 		if ((ids->value.int_val & 0xffff) == device_id)
1108 			return ids->value.int_val;
1109 	}
1110 
1111 	return 0;
1112 }
1113 
1114 static int
1115 acpi_video_bus_get_one_device(struct acpi_device *device,
1116 			      struct acpi_video_bus *video)
1117 {
1118 	unsigned long long device_id;
1119 	int status, device_type;
1120 	struct acpi_video_device *data;
1121 	struct acpi_video_device_attrib *attribute;
1122 
1123 	status =
1124 	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1125 	/* Some device omits _ADR, we skip them instead of fail */
1126 	if (ACPI_FAILURE(status))
1127 		return 0;
1128 
1129 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1130 	if (!data)
1131 		return -ENOMEM;
1132 
1133 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1134 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1135 	device->driver_data = data;
1136 
1137 	data->device_id = device_id;
1138 	data->video = video;
1139 	data->dev = device;
1140 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1141 			  acpi_video_switch_brightness);
1142 
1143 	attribute = acpi_video_get_device_attr(video, device_id);
1144 
1145 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1146 		switch (attribute->display_type) {
1147 		case ACPI_VIDEO_DISPLAY_CRT:
1148 			data->flags.crt = 1;
1149 			break;
1150 		case ACPI_VIDEO_DISPLAY_TV:
1151 			data->flags.tvout = 1;
1152 			break;
1153 		case ACPI_VIDEO_DISPLAY_DVI:
1154 			data->flags.dvi = 1;
1155 			break;
1156 		case ACPI_VIDEO_DISPLAY_LCD:
1157 			data->flags.lcd = 1;
1158 			break;
1159 		default:
1160 			data->flags.unknown = 1;
1161 			break;
1162 		}
1163 		if (attribute->bios_can_detect)
1164 			data->flags.bios = 1;
1165 	} else {
1166 		/* Check for legacy IDs */
1167 		device_type = acpi_video_get_device_type(video, device_id);
1168 		/* Ignore bits 16 and 18-20 */
1169 		switch (device_type & 0xffe2ffff) {
1170 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1171 			data->flags.crt = 1;
1172 			break;
1173 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1174 			data->flags.lcd = 1;
1175 			break;
1176 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1177 			data->flags.tvout = 1;
1178 			break;
1179 		default:
1180 			data->flags.unknown = 1;
1181 		}
1182 	}
1183 
1184 	acpi_video_device_bind(video, data);
1185 	acpi_video_device_find_cap(data);
1186 
1187 	mutex_lock(&video->device_list_lock);
1188 	list_add_tail(&data->entry, &video->video_device_list);
1189 	mutex_unlock(&video->device_list_lock);
1190 
1191 	return status;
1192 }
1193 
1194 /*
1195  *  Arg:
1196  *	video	: video bus device
1197  *
1198  *  Return:
1199  *	none
1200  *
1201  *  Enumerate the video device list of the video bus,
1202  *  bind the ids with the corresponding video devices
1203  *  under the video bus.
1204  */
1205 
1206 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1207 {
1208 	struct acpi_video_device *dev;
1209 
1210 	mutex_lock(&video->device_list_lock);
1211 
1212 	list_for_each_entry(dev, &video->video_device_list, entry)
1213 		acpi_video_device_bind(video, dev);
1214 
1215 	mutex_unlock(&video->device_list_lock);
1216 }
1217 
1218 /*
1219  *  Arg:
1220  *	video	: video bus device
1221  *	device	: video output device under the video
1222  *		bus
1223  *
1224  *  Return:
1225  *	none
1226  *
1227  *  Bind the ids with the corresponding video devices
1228  *  under the video bus.
1229  */
1230 
1231 static void
1232 acpi_video_device_bind(struct acpi_video_bus *video,
1233 		       struct acpi_video_device *device)
1234 {
1235 	struct acpi_video_enumerated_device *ids;
1236 	int i;
1237 
1238 	for (i = 0; i < video->attached_count; i++) {
1239 		ids = &video->attached_array[i];
1240 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1241 			ids->bind_info = device;
1242 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1243 		}
1244 	}
1245 }
1246 
1247 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1248 {
1249 	struct acpi_video_bus *video = device->video;
1250 	int i;
1251 
1252 	/*
1253 	 * If we have a broken _DOD or we have more than 8 output devices
1254 	 * under the graphics controller node that we can't proper deal with
1255 	 * in the operation region code currently, no need to test.
1256 	 */
1257 	if (!video->attached_count || video->child_count > 8)
1258 		return true;
1259 
1260 	for (i = 0; i < video->attached_count; i++) {
1261 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1262 		    (device->device_id & 0xfff))
1263 			return true;
1264 	}
1265 
1266 	return false;
1267 }
1268 
1269 /*
1270  *  Arg:
1271  *	video	: video bus device
1272  *
1273  *  Return:
1274  *	< 0	: error
1275  *
1276  *  Call _DOD to enumerate all devices attached to display adapter
1277  *
1278  */
1279 
1280 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1281 {
1282 	int status;
1283 	int count;
1284 	int i;
1285 	struct acpi_video_enumerated_device *active_list;
1286 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1287 	union acpi_object *dod = NULL;
1288 	union acpi_object *obj;
1289 
1290 	if (!video->cap._DOD)
1291 		return AE_NOT_EXIST;
1292 
1293 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1294 	if (!ACPI_SUCCESS(status)) {
1295 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1296 		return status;
1297 	}
1298 
1299 	dod = buffer.pointer;
1300 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1301 		ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1302 		status = -EFAULT;
1303 		goto out;
1304 	}
1305 
1306 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1307 			  dod->package.count));
1308 
1309 	active_list = kcalloc(1 + dod->package.count,
1310 			      sizeof(struct acpi_video_enumerated_device),
1311 			      GFP_KERNEL);
1312 	if (!active_list) {
1313 		status = -ENOMEM;
1314 		goto out;
1315 	}
1316 
1317 	count = 0;
1318 	for (i = 0; i < dod->package.count; i++) {
1319 		obj = &dod->package.elements[i];
1320 
1321 		if (obj->type != ACPI_TYPE_INTEGER) {
1322 			printk(KERN_ERR PREFIX
1323 				"Invalid _DOD data in element %d\n", i);
1324 			continue;
1325 		}
1326 
1327 		active_list[count].value.int_val = obj->integer.value;
1328 		active_list[count].bind_info = NULL;
1329 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1330 				  (int)obj->integer.value));
1331 		count++;
1332 	}
1333 
1334 	kfree(video->attached_array);
1335 
1336 	video->attached_array = active_list;
1337 	video->attached_count = count;
1338 
1339 out:
1340 	kfree(buffer.pointer);
1341 	return status;
1342 }
1343 
1344 static int
1345 acpi_video_get_next_level(struct acpi_video_device *device,
1346 			  u32 level_current, u32 event)
1347 {
1348 	int min, max, min_above, max_below, i, l, delta = 255;
1349 	max = max_below = 0;
1350 	min = min_above = 255;
1351 	/* Find closest level to level_current */
1352 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1353 		l = device->brightness->levels[i];
1354 		if (abs(l - level_current) < abs(delta)) {
1355 			delta = l - level_current;
1356 			if (!delta)
1357 				break;
1358 		}
1359 	}
1360 	/* Ajust level_current to closest available level */
1361 	level_current += delta;
1362 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1363 		l = device->brightness->levels[i];
1364 		if (l < min)
1365 			min = l;
1366 		if (l > max)
1367 			max = l;
1368 		if (l < min_above && l > level_current)
1369 			min_above = l;
1370 		if (l > max_below && l < level_current)
1371 			max_below = l;
1372 	}
1373 
1374 	switch (event) {
1375 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1376 		return (level_current < max) ? min_above : min;
1377 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1378 		return (level_current < max) ? min_above : max;
1379 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1380 		return (level_current > min) ? max_below : min;
1381 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1382 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1383 		return 0;
1384 	default:
1385 		return level_current;
1386 	}
1387 }
1388 
1389 static void
1390 acpi_video_switch_brightness(struct work_struct *work)
1391 {
1392 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1393 			     struct acpi_video_device, switch_brightness_work);
1394 	unsigned long long level_current, level_next;
1395 	int event = device->switch_brightness_event;
1396 	int result = -EINVAL;
1397 
1398 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1399 	if (!device->backlight)
1400 		return;
1401 
1402 	if (!device->brightness)
1403 		goto out;
1404 
1405 	result = acpi_video_device_lcd_get_level_current(device,
1406 							 &level_current,
1407 							 false);
1408 	if (result)
1409 		goto out;
1410 
1411 	level_next = acpi_video_get_next_level(device, level_current, event);
1412 
1413 	result = acpi_video_device_lcd_set_level(device, level_next);
1414 
1415 	if (!result)
1416 		backlight_force_update(device->backlight,
1417 				       BACKLIGHT_UPDATE_HOTKEY);
1418 
1419 out:
1420 	if (result)
1421 		printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1422 }
1423 
1424 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1425 			void **edid)
1426 {
1427 	struct acpi_video_bus *video;
1428 	struct acpi_video_device *video_device;
1429 	union acpi_object *buffer = NULL;
1430 	acpi_status status;
1431 	int i, length;
1432 
1433 	if (!device || !acpi_driver_data(device))
1434 		return -EINVAL;
1435 
1436 	video = acpi_driver_data(device);
1437 
1438 	for (i = 0; i < video->attached_count; i++) {
1439 		video_device = video->attached_array[i].bind_info;
1440 		length = 256;
1441 
1442 		if (!video_device)
1443 			continue;
1444 
1445 		if (!video_device->cap._DDC)
1446 			continue;
1447 
1448 		if (type) {
1449 			switch (type) {
1450 			case ACPI_VIDEO_DISPLAY_CRT:
1451 				if (!video_device->flags.crt)
1452 					continue;
1453 				break;
1454 			case ACPI_VIDEO_DISPLAY_TV:
1455 				if (!video_device->flags.tvout)
1456 					continue;
1457 				break;
1458 			case ACPI_VIDEO_DISPLAY_DVI:
1459 				if (!video_device->flags.dvi)
1460 					continue;
1461 				break;
1462 			case ACPI_VIDEO_DISPLAY_LCD:
1463 				if (!video_device->flags.lcd)
1464 					continue;
1465 				break;
1466 			}
1467 		} else if (video_device->device_id != device_id) {
1468 			continue;
1469 		}
1470 
1471 		status = acpi_video_device_EDID(video_device, &buffer, length);
1472 
1473 		if (ACPI_FAILURE(status) || !buffer ||
1474 		    buffer->type != ACPI_TYPE_BUFFER) {
1475 			length = 128;
1476 			status = acpi_video_device_EDID(video_device, &buffer,
1477 							length);
1478 			if (ACPI_FAILURE(status) || !buffer ||
1479 			    buffer->type != ACPI_TYPE_BUFFER) {
1480 				continue;
1481 			}
1482 		}
1483 
1484 		*edid = buffer->buffer.pointer;
1485 		return length;
1486 	}
1487 
1488 	return -ENODEV;
1489 }
1490 EXPORT_SYMBOL(acpi_video_get_edid);
1491 
1492 static int
1493 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1494 			   struct acpi_device *device)
1495 {
1496 	int status = 0;
1497 	struct acpi_device *dev;
1498 
1499 	/*
1500 	 * There are systems where video module known to work fine regardless
1501 	 * of broken _DOD and ignoring returned value here doesn't cause
1502 	 * any issues later.
1503 	 */
1504 	acpi_video_device_enumerate(video);
1505 
1506 	list_for_each_entry(dev, &device->children, node) {
1507 
1508 		status = acpi_video_bus_get_one_device(dev, video);
1509 		if (status) {
1510 			dev_err(&dev->dev, "Can't attach device\n");
1511 			break;
1512 		}
1513 		video->child_count++;
1514 	}
1515 	return status;
1516 }
1517 
1518 /* acpi_video interface */
1519 
1520 /*
1521  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1522  * preform any automatic brightness change on receiving a notification.
1523  */
1524 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1525 {
1526 	return acpi_video_bus_DOS(video, 0,
1527 				  acpi_osi_is_win8() ? 1 : 0);
1528 }
1529 
1530 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1531 {
1532 	return acpi_video_bus_DOS(video, 0,
1533 				  acpi_osi_is_win8() ? 0 : 1);
1534 }
1535 
1536 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1537 {
1538 	struct acpi_video_bus *video = acpi_driver_data(device);
1539 	struct input_dev *input;
1540 	int keycode = 0;
1541 
1542 	if (!video || !video->input)
1543 		return;
1544 
1545 	input = video->input;
1546 
1547 	switch (event) {
1548 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1549 					 * most likely via hotkey. */
1550 		keycode = KEY_SWITCHVIDEOMODE;
1551 		break;
1552 
1553 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1554 					 * connector. */
1555 		acpi_video_device_enumerate(video);
1556 		acpi_video_device_rebind(video);
1557 		keycode = KEY_SWITCHVIDEOMODE;
1558 		break;
1559 
1560 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1561 		keycode = KEY_SWITCHVIDEOMODE;
1562 		break;
1563 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1564 		keycode = KEY_VIDEO_NEXT;
1565 		break;
1566 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1567 		keycode = KEY_VIDEO_PREV;
1568 		break;
1569 
1570 	default:
1571 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1572 				  "Unsupported event [0x%x]\n", event));
1573 		break;
1574 	}
1575 
1576 	if (acpi_notifier_call_chain(device, event, 0))
1577 		/* Something vetoed the keypress. */
1578 		keycode = 0;
1579 
1580 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1581 		input_report_key(input, keycode, 1);
1582 		input_sync(input);
1583 		input_report_key(input, keycode, 0);
1584 		input_sync(input);
1585 	}
1586 
1587 	return;
1588 }
1589 
1590 static void brightness_switch_event(struct acpi_video_device *video_device,
1591 				    u32 event)
1592 {
1593 	if (!brightness_switch_enabled)
1594 		return;
1595 
1596 	video_device->switch_brightness_event = event;
1597 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1598 }
1599 
1600 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1601 {
1602 	struct acpi_video_device *video_device = data;
1603 	struct acpi_device *device = NULL;
1604 	struct acpi_video_bus *bus;
1605 	struct input_dev *input;
1606 	int keycode = 0;
1607 
1608 	if (!video_device)
1609 		return;
1610 
1611 	device = video_device->dev;
1612 	bus = video_device->video;
1613 	input = bus->input;
1614 
1615 	switch (event) {
1616 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1617 		brightness_switch_event(video_device, event);
1618 		keycode = KEY_BRIGHTNESS_CYCLE;
1619 		break;
1620 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1621 		brightness_switch_event(video_device, event);
1622 		keycode = KEY_BRIGHTNESSUP;
1623 		break;
1624 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1625 		brightness_switch_event(video_device, event);
1626 		keycode = KEY_BRIGHTNESSDOWN;
1627 		break;
1628 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1629 		brightness_switch_event(video_device, event);
1630 		keycode = KEY_BRIGHTNESS_ZERO;
1631 		break;
1632 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1633 		brightness_switch_event(video_device, event);
1634 		keycode = KEY_DISPLAY_OFF;
1635 		break;
1636 	default:
1637 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1638 				  "Unsupported event [0x%x]\n", event));
1639 		break;
1640 	}
1641 
1642 	acpi_notifier_call_chain(device, event, 0);
1643 
1644 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1645 		input_report_key(input, keycode, 1);
1646 		input_sync(input);
1647 		input_report_key(input, keycode, 0);
1648 		input_sync(input);
1649 	}
1650 
1651 	return;
1652 }
1653 
1654 static int acpi_video_resume(struct notifier_block *nb,
1655 				unsigned long val, void *ign)
1656 {
1657 	struct acpi_video_bus *video;
1658 	struct acpi_video_device *video_device;
1659 	int i;
1660 
1661 	switch (val) {
1662 	case PM_HIBERNATION_PREPARE:
1663 	case PM_SUSPEND_PREPARE:
1664 	case PM_RESTORE_PREPARE:
1665 		return NOTIFY_DONE;
1666 	}
1667 
1668 	video = container_of(nb, struct acpi_video_bus, pm_nb);
1669 
1670 	dev_info(&video->device->dev, "Restoring backlight state\n");
1671 
1672 	for (i = 0; i < video->attached_count; i++) {
1673 		video_device = video->attached_array[i].bind_info;
1674 		if (video_device && video_device->brightness)
1675 			acpi_video_device_lcd_set_level(video_device,
1676 					video_device->brightness->curr);
1677 	}
1678 
1679 	return NOTIFY_OK;
1680 }
1681 
1682 static acpi_status
1683 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1684 			void **return_value)
1685 {
1686 	struct acpi_device *device = context;
1687 	struct acpi_device *sibling;
1688 	int result;
1689 
1690 	if (handle == device->handle)
1691 		return AE_CTRL_TERMINATE;
1692 
1693 	result = acpi_bus_get_device(handle, &sibling);
1694 	if (result)
1695 		return AE_OK;
1696 
1697 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1698 			return AE_ALREADY_EXISTS;
1699 
1700 	return AE_OK;
1701 }
1702 
1703 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1704 {
1705 	struct backlight_properties props;
1706 	struct pci_dev *pdev;
1707 	acpi_handle acpi_parent;
1708 	struct device *parent = NULL;
1709 	int result;
1710 	static int count;
1711 	char *name;
1712 
1713 	result = acpi_video_init_brightness(device);
1714 	if (result)
1715 		return;
1716 
1717 	if (disable_backlight_sysfs_if > 0)
1718 		return;
1719 
1720 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1721 	if (!name)
1722 		return;
1723 	count++;
1724 
1725 	acpi_get_parent(device->dev->handle, &acpi_parent);
1726 
1727 	pdev = acpi_get_pci_dev(acpi_parent);
1728 	if (pdev) {
1729 		parent = &pdev->dev;
1730 		pci_dev_put(pdev);
1731 	}
1732 
1733 	memset(&props, 0, sizeof(struct backlight_properties));
1734 	props.type = BACKLIGHT_FIRMWARE;
1735 	props.max_brightness =
1736 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1737 	device->backlight = backlight_device_register(name,
1738 						      parent,
1739 						      device,
1740 						      &acpi_backlight_ops,
1741 						      &props);
1742 	kfree(name);
1743 	if (IS_ERR(device->backlight)) {
1744 		device->backlight = NULL;
1745 		return;
1746 	}
1747 
1748 	/*
1749 	 * Save current brightness level in case we have to restore it
1750 	 * before acpi_video_device_lcd_set_level() is called next time.
1751 	 */
1752 	device->backlight->props.brightness =
1753 			acpi_video_get_brightness(device->backlight);
1754 
1755 	device->cooling_dev = thermal_cooling_device_register("LCD",
1756 				device->dev, &video_cooling_ops);
1757 	if (IS_ERR(device->cooling_dev)) {
1758 		/*
1759 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1760 		 * Also, why the hell we are returning early and not attempt to
1761 		 * register video output if cooling device registration failed?
1762 		 * -- dtor
1763 		 */
1764 		device->cooling_dev = NULL;
1765 		return;
1766 	}
1767 
1768 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1769 		 device->cooling_dev->id);
1770 	result = sysfs_create_link(&device->dev->dev.kobj,
1771 			&device->cooling_dev->device.kobj,
1772 			"thermal_cooling");
1773 	if (result)
1774 		printk(KERN_ERR PREFIX "Create sysfs link\n");
1775 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1776 			&device->dev->dev.kobj, "device");
1777 	if (result)
1778 		printk(KERN_ERR PREFIX "Create sysfs link\n");
1779 }
1780 
1781 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1782 {
1783 	struct acpi_video_device *dev;
1784 	union acpi_object *levels;
1785 
1786 	mutex_lock(&video->device_list_lock);
1787 	list_for_each_entry(dev, &video->video_device_list, entry) {
1788 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1789 			kfree(levels);
1790 	}
1791 	mutex_unlock(&video->device_list_lock);
1792 }
1793 
1794 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1795 {
1796 	/*
1797 	 * Do not create backlight device for video output
1798 	 * device that is not in the enumerated list.
1799 	 */
1800 	if (!acpi_video_device_in_dod(dev)) {
1801 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1802 		return false;
1803 	}
1804 
1805 	if (only_lcd)
1806 		return dev->flags.lcd;
1807 	return true;
1808 }
1809 
1810 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1811 {
1812 	struct acpi_video_device *dev;
1813 
1814 	if (video->backlight_registered)
1815 		return 0;
1816 
1817 	acpi_video_run_bcl_for_osi(video);
1818 
1819 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1820 		return 0;
1821 
1822 	mutex_lock(&video->device_list_lock);
1823 	list_for_each_entry(dev, &video->video_device_list, entry) {
1824 		if (acpi_video_should_register_backlight(dev))
1825 			acpi_video_dev_register_backlight(dev);
1826 	}
1827 	mutex_unlock(&video->device_list_lock);
1828 
1829 	video->backlight_registered = true;
1830 
1831 	video->pm_nb.notifier_call = acpi_video_resume;
1832 	video->pm_nb.priority = 0;
1833 	return register_pm_notifier(&video->pm_nb);
1834 }
1835 
1836 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1837 {
1838 	if (device->backlight) {
1839 		backlight_device_unregister(device->backlight);
1840 		device->backlight = NULL;
1841 	}
1842 	if (device->brightness) {
1843 		kfree(device->brightness->levels);
1844 		kfree(device->brightness);
1845 		device->brightness = NULL;
1846 	}
1847 	if (device->cooling_dev) {
1848 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1849 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1850 		thermal_cooling_device_unregister(device->cooling_dev);
1851 		device->cooling_dev = NULL;
1852 	}
1853 }
1854 
1855 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1856 {
1857 	struct acpi_video_device *dev;
1858 	int error;
1859 
1860 	if (!video->backlight_registered)
1861 		return 0;
1862 
1863 	error = unregister_pm_notifier(&video->pm_nb);
1864 
1865 	mutex_lock(&video->device_list_lock);
1866 	list_for_each_entry(dev, &video->video_device_list, entry)
1867 		acpi_video_dev_unregister_backlight(dev);
1868 	mutex_unlock(&video->device_list_lock);
1869 
1870 	video->backlight_registered = false;
1871 
1872 	return error;
1873 }
1874 
1875 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1876 {
1877 	acpi_status status;
1878 	struct acpi_device *adev = device->dev;
1879 
1880 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1881 					     acpi_video_device_notify, device);
1882 	if (ACPI_FAILURE(status))
1883 		dev_err(&adev->dev, "Error installing notify handler\n");
1884 	else
1885 		device->flags.notify = 1;
1886 }
1887 
1888 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1889 {
1890 	struct input_dev *input;
1891 	struct acpi_video_device *dev;
1892 	int error;
1893 
1894 	video->input = input = input_allocate_device();
1895 	if (!input) {
1896 		error = -ENOMEM;
1897 		goto out;
1898 	}
1899 
1900 	error = acpi_video_bus_start_devices(video);
1901 	if (error)
1902 		goto err_free_input;
1903 
1904 	snprintf(video->phys, sizeof(video->phys),
1905 			"%s/video/input0", acpi_device_hid(video->device));
1906 
1907 	input->name = acpi_device_name(video->device);
1908 	input->phys = video->phys;
1909 	input->id.bustype = BUS_HOST;
1910 	input->id.product = 0x06;
1911 	input->dev.parent = &video->device->dev;
1912 	input->evbit[0] = BIT(EV_KEY);
1913 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1914 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1915 	set_bit(KEY_VIDEO_PREV, input->keybit);
1916 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1917 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1918 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1919 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1920 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1921 
1922 	error = input_register_device(input);
1923 	if (error)
1924 		goto err_stop_dev;
1925 
1926 	mutex_lock(&video->device_list_lock);
1927 	list_for_each_entry(dev, &video->video_device_list, entry)
1928 		acpi_video_dev_add_notify_handler(dev);
1929 	mutex_unlock(&video->device_list_lock);
1930 
1931 	return 0;
1932 
1933 err_stop_dev:
1934 	acpi_video_bus_stop_devices(video);
1935 err_free_input:
1936 	input_free_device(input);
1937 	video->input = NULL;
1938 out:
1939 	return error;
1940 }
1941 
1942 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1943 {
1944 	if (dev->flags.notify) {
1945 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1946 					   acpi_video_device_notify);
1947 		dev->flags.notify = 0;
1948 	}
1949 }
1950 
1951 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1952 {
1953 	struct acpi_video_device *dev;
1954 
1955 	mutex_lock(&video->device_list_lock);
1956 	list_for_each_entry(dev, &video->video_device_list, entry)
1957 		acpi_video_dev_remove_notify_handler(dev);
1958 	mutex_unlock(&video->device_list_lock);
1959 
1960 	acpi_video_bus_stop_devices(video);
1961 	input_unregister_device(video->input);
1962 	video->input = NULL;
1963 }
1964 
1965 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1966 {
1967 	struct acpi_video_device *dev, *next;
1968 
1969 	mutex_lock(&video->device_list_lock);
1970 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1971 		list_del(&dev->entry);
1972 		kfree(dev);
1973 	}
1974 	mutex_unlock(&video->device_list_lock);
1975 
1976 	return 0;
1977 }
1978 
1979 static int instance;
1980 
1981 static int acpi_video_bus_add(struct acpi_device *device)
1982 {
1983 	struct acpi_video_bus *video;
1984 	int error;
1985 	acpi_status status;
1986 
1987 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1988 				device->parent->handle, 1,
1989 				acpi_video_bus_match, NULL,
1990 				device, NULL);
1991 	if (status == AE_ALREADY_EXISTS) {
1992 		printk(KERN_WARNING FW_BUG
1993 			"Duplicate ACPI video bus devices for the"
1994 			" same VGA controller, please try module "
1995 			"parameter \"video.allow_duplicates=1\""
1996 			"if the current driver doesn't work.\n");
1997 		if (!allow_duplicates)
1998 			return -ENODEV;
1999 	}
2000 
2001 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2002 	if (!video)
2003 		return -ENOMEM;
2004 
2005 	/* a hack to fix the duplicate name "VID" problem on T61 */
2006 	if (!strcmp(device->pnp.bus_id, "VID")) {
2007 		if (instance)
2008 			device->pnp.bus_id[3] = '0' + instance;
2009 		instance++;
2010 	}
2011 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2012 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2013 		if (instance)
2014 			device->pnp.bus_id[3] = '0' + instance;
2015 		instance++;
2016 	}
2017 
2018 	video->device = device;
2019 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2020 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2021 	device->driver_data = video;
2022 
2023 	acpi_video_bus_find_cap(video);
2024 	error = acpi_video_bus_check(video);
2025 	if (error)
2026 		goto err_free_video;
2027 
2028 	mutex_init(&video->device_list_lock);
2029 	INIT_LIST_HEAD(&video->video_device_list);
2030 
2031 	error = acpi_video_bus_get_devices(video, device);
2032 	if (error)
2033 		goto err_put_video;
2034 
2035 	printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2036 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2037 	       video->flags.multihead ? "yes" : "no",
2038 	       video->flags.rom ? "yes" : "no",
2039 	       video->flags.post ? "yes" : "no");
2040 	mutex_lock(&video_list_lock);
2041 	list_add_tail(&video->entry, &video_bus_head);
2042 	mutex_unlock(&video_list_lock);
2043 
2044 	acpi_video_bus_register_backlight(video);
2045 	acpi_video_bus_add_notify_handler(video);
2046 
2047 	return 0;
2048 
2049 err_put_video:
2050 	acpi_video_bus_put_devices(video);
2051 	kfree(video->attached_array);
2052 err_free_video:
2053 	kfree(video);
2054 	device->driver_data = NULL;
2055 
2056 	return error;
2057 }
2058 
2059 static int acpi_video_bus_remove(struct acpi_device *device)
2060 {
2061 	struct acpi_video_bus *video = NULL;
2062 
2063 
2064 	if (!device || !acpi_driver_data(device))
2065 		return -EINVAL;
2066 
2067 	video = acpi_driver_data(device);
2068 
2069 	acpi_video_bus_remove_notify_handler(video);
2070 	acpi_video_bus_unregister_backlight(video);
2071 	acpi_video_bus_put_devices(video);
2072 
2073 	mutex_lock(&video_list_lock);
2074 	list_del(&video->entry);
2075 	mutex_unlock(&video_list_lock);
2076 
2077 	kfree(video->attached_array);
2078 	kfree(video);
2079 
2080 	return 0;
2081 }
2082 
2083 static int __init is_i740(struct pci_dev *dev)
2084 {
2085 	if (dev->device == 0x00D1)
2086 		return 1;
2087 	if (dev->device == 0x7000)
2088 		return 1;
2089 	return 0;
2090 }
2091 
2092 static int __init intel_opregion_present(void)
2093 {
2094 	int opregion = 0;
2095 	struct pci_dev *dev = NULL;
2096 	u32 address;
2097 
2098 	for_each_pci_dev(dev) {
2099 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2100 			continue;
2101 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2102 			continue;
2103 		/* We don't want to poke around undefined i740 registers */
2104 		if (is_i740(dev))
2105 			continue;
2106 		pci_read_config_dword(dev, 0xfc, &address);
2107 		if (!address)
2108 			continue;
2109 		opregion = 1;
2110 	}
2111 	return opregion;
2112 }
2113 
2114 /* Check if the chassis-type indicates there is no builtin LCD panel */
2115 static bool dmi_is_desktop(void)
2116 {
2117 	const char *chassis_type;
2118 	unsigned long type;
2119 
2120 	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2121 	if (!chassis_type)
2122 		return false;
2123 
2124 	if (kstrtoul(chassis_type, 10, &type) != 0)
2125 		return false;
2126 
2127 	switch (type) {
2128 	case 0x03: /* Desktop */
2129 	case 0x04: /* Low Profile Desktop */
2130 	case 0x05: /* Pizza Box */
2131 	case 0x06: /* Mini Tower */
2132 	case 0x07: /* Tower */
2133 	case 0x10: /* Lunch Box */
2134 	case 0x11: /* Main Server Chassis */
2135 		return true;
2136 	}
2137 
2138 	return false;
2139 }
2140 
2141 int acpi_video_register(void)
2142 {
2143 	int ret = 0;
2144 
2145 	mutex_lock(&register_count_mutex);
2146 	if (register_count) {
2147 		/*
2148 		 * if the function of acpi_video_register is already called,
2149 		 * don't register the acpi_vide_bus again and return no error.
2150 		 */
2151 		goto leave;
2152 	}
2153 
2154 	/*
2155 	 * We're seeing a lot of bogus backlight interfaces on newer machines
2156 	 * without a LCD such as desktops, servers and HDMI sticks. Checking
2157 	 * the lcd flag fixes this, so enable this on any machines which are
2158 	 * win8 ready (where we also prefer the native backlight driver, so
2159 	 * normally the acpi_video code should not register there anyways).
2160 	 */
2161 	if (only_lcd == -1) {
2162 		if (dmi_is_desktop() && acpi_osi_is_win8())
2163 			only_lcd = true;
2164 		else
2165 			only_lcd = false;
2166 	}
2167 
2168 	dmi_check_system(video_dmi_table);
2169 
2170 	ret = acpi_bus_register_driver(&acpi_video_bus);
2171 	if (ret)
2172 		goto leave;
2173 
2174 	/*
2175 	 * When the acpi_video_bus is loaded successfully, increase
2176 	 * the counter reference.
2177 	 */
2178 	register_count = 1;
2179 
2180 leave:
2181 	mutex_unlock(&register_count_mutex);
2182 	return ret;
2183 }
2184 EXPORT_SYMBOL(acpi_video_register);
2185 
2186 void acpi_video_unregister(void)
2187 {
2188 	mutex_lock(&register_count_mutex);
2189 	if (register_count) {
2190 		acpi_bus_unregister_driver(&acpi_video_bus);
2191 		register_count = 0;
2192 	}
2193 	mutex_unlock(&register_count_mutex);
2194 }
2195 EXPORT_SYMBOL(acpi_video_unregister);
2196 
2197 void acpi_video_unregister_backlight(void)
2198 {
2199 	struct acpi_video_bus *video;
2200 
2201 	mutex_lock(&register_count_mutex);
2202 	if (register_count) {
2203 		mutex_lock(&video_list_lock);
2204 		list_for_each_entry(video, &video_bus_head, entry)
2205 			acpi_video_bus_unregister_backlight(video);
2206 		mutex_unlock(&video_list_lock);
2207 	}
2208 	mutex_unlock(&register_count_mutex);
2209 }
2210 
2211 bool acpi_video_handles_brightness_key_presses(void)
2212 {
2213 	bool have_video_busses;
2214 
2215 	mutex_lock(&video_list_lock);
2216 	have_video_busses = !list_empty(&video_bus_head);
2217 	mutex_unlock(&video_list_lock);
2218 
2219 	return have_video_busses &&
2220 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2221 }
2222 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2223 
2224 /*
2225  * This is kind of nasty. Hardware using Intel chipsets may require
2226  * the video opregion code to be run first in order to initialise
2227  * state before any ACPI video calls are made. To handle this we defer
2228  * registration of the video class until the opregion code has run.
2229  */
2230 
2231 static int __init acpi_video_init(void)
2232 {
2233 	/*
2234 	 * Let the module load even if ACPI is disabled (e.g. due to
2235 	 * a broken BIOS) so that i915.ko can still be loaded on such
2236 	 * old systems without an AcpiOpRegion.
2237 	 *
2238 	 * acpi_video_register() will report -ENODEV later as well due
2239 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2240 	 */
2241 	if (acpi_disabled)
2242 		return 0;
2243 
2244 	if (intel_opregion_present())
2245 		return 0;
2246 
2247 	return acpi_video_register();
2248 }
2249 
2250 static void __exit acpi_video_exit(void)
2251 {
2252 	acpi_video_detect_exit();
2253 	acpi_video_unregister();
2254 
2255 	return;
2256 }
2257 
2258 module_init(acpi_video_init);
2259 module_exit(acpi_video_exit);
2260