xref: /linux/drivers/acpi/acpi_video.c (revision ef815d2cba782e96b9aad9483523d474ed41c62a)
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 #define pr_fmt(fmt) "ACPI: video: " fmt
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/types.h>
16 #include <linux/list.h>
17 #include <linux/mutex.h>
18 #include <linux/input.h>
19 #include <linux/backlight.h>
20 #include <linux/thermal.h>
21 #include <linux/sort.h>
22 #include <linux/pci.h>
23 #include <linux/pci_ids.h>
24 #include <linux/slab.h>
25 #include <linux/dmi.h>
26 #include <linux/suspend.h>
27 #include <linux/acpi.h>
28 #include <acpi/video.h>
29 #include <linux/uaccess.h>
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 MODULE_AUTHOR("Bruno Ducrot");
37 MODULE_DESCRIPTION("ACPI Video Driver");
38 MODULE_LICENSE("GPL");
39 
40 static bool brightness_switch_enabled = true;
41 module_param(brightness_switch_enabled, bool, 0644);
42 
43 /*
44  * By default, we don't allow duplicate ACPI video bus devices
45  * under the same VGA controller
46  */
47 static bool allow_duplicates;
48 module_param(allow_duplicates, bool, 0644);
49 
50 #define REPORT_OUTPUT_KEY_EVENTS		0x01
51 #define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
52 static int report_key_events = -1;
53 module_param(report_key_events, int, 0644);
54 MODULE_PARM_DESC(report_key_events,
55 	"0: none, 1: output changes, 2: brightness changes, 3: all");
56 
57 static int hw_changes_brightness = -1;
58 module_param(hw_changes_brightness, int, 0644);
59 MODULE_PARM_DESC(hw_changes_brightness,
60 	"Set this to 1 on buggy hw which changes the brightness itself when "
61 	"a hotkey is pressed: -1: auto, 0: normal 1: hw-changes-brightness");
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 bool may_report_brightness_keys;
74 static int register_count;
75 static DEFINE_MUTEX(register_count_mutex);
76 static DEFINE_MUTEX(video_list_lock);
77 static LIST_HEAD(video_bus_head);
78 static int acpi_video_bus_add(struct acpi_device *device);
79 static void acpi_video_bus_remove(struct acpi_device *device);
80 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
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_FAILURE(status))
324 		return status;
325 	obj = (union acpi_object *)buffer.pointer;
326 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
327 		acpi_handle_info(handle, "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_handle_info(device->dev->handle, "_BCM evaluation failed\n");
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_handle_info(device->dev->handle, "Current brightness invalid\n");
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_set_device_id_scheme(const struct dmi_system_id *d)
382 {
383 	device_id_scheme = true;
384 	return 0;
385 }
386 
387 static int video_enable_only_lcd(const struct dmi_system_id *d)
388 {
389 	only_lcd = true;
390 	return 0;
391 }
392 
393 static int video_set_report_key_events(const struct dmi_system_id *id)
394 {
395 	if (report_key_events == -1)
396 		report_key_events = (uintptr_t)id->driver_data;
397 	return 0;
398 }
399 
400 static int video_hw_changes_brightness(
401 	const struct dmi_system_id *d)
402 {
403 	if (hw_changes_brightness == -1)
404 		hw_changes_brightness = 1;
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 machine's _DOD IDs don't have bit 31(Device ID Scheme) set
455 	 * but the IDs actually follow the Device ID Scheme.
456 	 */
457 	{
458 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
459 	 .callback = video_set_device_id_scheme,
460 	 .ident = "ESPRIMO Mobile M9410",
461 	 .matches = {
462 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
463 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
464 		},
465 	},
466 	/*
467 	 * Some machines have multiple video output devices, but only the one
468 	 * that is the type of LCD can do the backlight control so we should not
469 	 * register backlight interface for other video output devices.
470 	 */
471 	{
472 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
473 	 .callback = video_enable_only_lcd,
474 	 .ident = "ESPRIMO Mobile M9410",
475 	 .matches = {
476 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
477 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
478 		},
479 	},
480 	/*
481 	 * Some machines report wrong key events on the acpi-bus, suppress
482 	 * key event reporting on these.  Note this is only intended to work
483 	 * around events which are plain wrong. In some cases we get double
484 	 * events, in this case acpi-video is considered the canonical source
485 	 * and the events from the other source should be filtered. E.g.
486 	 * by calling acpi_video_handles_brightness_key_presses() from the
487 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
488 	 */
489 	{
490 	 .callback = video_set_report_key_events,
491 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
492 	 .ident = "Dell Vostro V131",
493 	 .matches = {
494 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
495 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
496 		},
497 	},
498 	{
499 	 .callback = video_set_report_key_events,
500 	 .driver_data = (void *)((uintptr_t)REPORT_BRIGHTNESS_KEY_EVENTS),
501 	 .ident = "Dell Vostro 3350",
502 	 .matches = {
503 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
504 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3350"),
505 		},
506 	},
507 	/*
508 	 * Some machines change the brightness themselves when a brightness
509 	 * hotkey gets pressed, despite us telling them not to. In this case
510 	 * acpi_video_device_notify() should only call backlight_force_update(
511 	 * BACKLIGHT_UPDATE_HOTKEY) and not do anything else.
512 	 */
513 	{
514 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */
515 	 .callback = video_hw_changes_brightness,
516 	 .ident = "Packard Bell EasyNote MZ35",
517 	 .matches = {
518 		DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"),
519 		DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"),
520 		},
521 	},
522 	{}
523 };
524 
525 static unsigned long long
526 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
527 			      unsigned long long bqc_value)
528 {
529 	unsigned long long level;
530 
531 	if (device->brightness->flags._BQC_use_index) {
532 		/*
533 		 * _BQC returns an index that doesn't account for the first 2
534 		 * items with special meaning (see enum acpi_video_level_idx),
535 		 * so we need to compensate for that by offsetting ourselves
536 		 */
537 		if (device->brightness->flags._BCL_reversed)
538 			bqc_value = device->brightness->count -
539 				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
540 
541 		level = device->brightness->levels[bqc_value +
542 						   ACPI_VIDEO_FIRST_LEVEL];
543 	} else {
544 		level = bqc_value;
545 	}
546 
547 	level += bqc_offset_aml_bug_workaround;
548 
549 	return level;
550 }
551 
552 static int
553 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
554 					unsigned long long *level, bool raw)
555 {
556 	acpi_status status = AE_OK;
557 	int i;
558 
559 	if (device->cap._BQC || device->cap._BCQ) {
560 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
561 
562 		status = acpi_evaluate_integer(device->dev->handle, buf,
563 						NULL, level);
564 		if (ACPI_SUCCESS(status)) {
565 			if (raw) {
566 				/*
567 				 * Caller has indicated he wants the raw
568 				 * value returned by _BQC, so don't furtherly
569 				 * mess with the value.
570 				 */
571 				return 0;
572 			}
573 
574 			*level = acpi_video_bqc_value_to_level(device, *level);
575 
576 			for (i = ACPI_VIDEO_FIRST_LEVEL;
577 			     i < device->brightness->count; i++)
578 				if (device->brightness->levels[i] == *level) {
579 					device->brightness->curr = *level;
580 					return 0;
581 				}
582 			/*
583 			 * BQC returned an invalid level.
584 			 * Stop using it.
585 			 */
586 			acpi_handle_info(device->dev->handle,
587 					 "%s returned an invalid level", buf);
588 			device->cap._BQC = device->cap._BCQ = 0;
589 		} else {
590 			/*
591 			 * Fixme:
592 			 * should we return an error or ignore this failure?
593 			 * dev->brightness->curr is a cached value which stores
594 			 * the correct current backlight level in most cases.
595 			 * ACPI video backlight still works w/ buggy _BQC.
596 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
597 			 */
598 			acpi_handle_info(device->dev->handle,
599 					 "%s evaluation failed", buf);
600 			device->cap._BQC = device->cap._BCQ = 0;
601 		}
602 	}
603 
604 	*level = device->brightness->curr;
605 	return 0;
606 }
607 
608 static int
609 acpi_video_device_EDID(struct acpi_video_device *device,
610 		       union acpi_object **edid, ssize_t length)
611 {
612 	int status;
613 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
614 	union acpi_object *obj;
615 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
616 	struct acpi_object_list args = { 1, &arg0 };
617 
618 
619 	*edid = NULL;
620 
621 	if (!device)
622 		return -ENODEV;
623 	if (length == 128)
624 		arg0.integer.value = 1;
625 	else if (length == 256)
626 		arg0.integer.value = 2;
627 	else
628 		return -EINVAL;
629 
630 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
631 	if (ACPI_FAILURE(status))
632 		return -ENODEV;
633 
634 	obj = buffer.pointer;
635 
636 	if (obj && obj->type == ACPI_TYPE_BUFFER)
637 		*edid = obj;
638 	else {
639 		acpi_handle_info(device->dev->handle, "Invalid _DDC data\n");
640 		status = -EFAULT;
641 		kfree(obj);
642 	}
643 
644 	return status;
645 }
646 
647 /* bus */
648 
649 /*
650  *  Arg:
651  *	video		: video bus device pointer
652  *	bios_flag	:
653  *		0.	The system BIOS should NOT automatically switch(toggle)
654  *			the active display output.
655  *		1.	The system BIOS should automatically switch (toggle) the
656  *			active display output. No switch event.
657  *		2.	The _DGS value should be locked.
658  *		3.	The system BIOS should not automatically switch (toggle) the
659  *			active display output, but instead generate the display switch
660  *			event notify code.
661  *	lcd_flag	:
662  *		0.	The system BIOS should automatically control the brightness level
663  *			of the LCD when:
664  *			- the power changes from AC to DC (ACPI appendix B)
665  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
666  *		1.	The system BIOS should NOT automatically control the brightness
667  *			level of the LCD when:
668  *			- the power changes from AC to DC (ACPI appendix B)
669  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
670  *  Return Value:
671  *		-EINVAL	wrong arg.
672  */
673 
674 static int
675 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
676 {
677 	acpi_status status;
678 
679 	if (!video->cap._DOS)
680 		return 0;
681 
682 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
683 		return -EINVAL;
684 	video->dos_setting = (lcd_flag << 2) | bios_flag;
685 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
686 					    (lcd_flag << 2) | bios_flag);
687 	if (ACPI_FAILURE(status))
688 		return -EIO;
689 
690 	return 0;
691 }
692 
693 /*
694  * Simple comparison function used to sort backlight levels.
695  */
696 
697 static int
698 acpi_video_cmp_level(const void *a, const void *b)
699 {
700 	return *(int *)a - *(int *)b;
701 }
702 
703 /*
704  * Decides if _BQC/_BCQ for this system is usable
705  *
706  * We do this by changing the level first and then read out the current
707  * brightness level, if the value does not match, find out if it is using
708  * index. If not, clear the _BQC/_BCQ capability.
709  */
710 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
711 				int max_level, int current_level)
712 {
713 	struct acpi_video_device_brightness *br = device->brightness;
714 	int result;
715 	unsigned long long level;
716 	int test_level;
717 
718 	/* don't mess with existing known broken systems */
719 	if (bqc_offset_aml_bug_workaround)
720 		return 0;
721 
722 	/*
723 	 * Some systems always report current brightness level as maximum
724 	 * through _BQC, we need to test another value for them. However,
725 	 * there is a subtlety:
726 	 *
727 	 * If the _BCL package ordering is descending, the first level
728 	 * (br->levels[2]) is likely to be 0, and if the number of levels
729 	 * matches the number of steps, we might confuse a returned level to
730 	 * mean the index.
731 	 *
732 	 * For example:
733 	 *
734 	 *     current_level = max_level = 100
735 	 *     test_level = 0
736 	 *     returned level = 100
737 	 *
738 	 * In this case 100 means the level, not the index, and _BCM failed.
739 	 * Still, if the _BCL package ordering is descending, the index of
740 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
741 	 *
742 	 * This causes all _BQC calls to return bogus values causing weird
743 	 * behavior from the user's perspective.  For example:
744 	 *
745 	 * xbacklight -set 10; xbacklight -set 20;
746 	 *
747 	 * would flash to 90% and then slowly down to the desired level (20).
748 	 *
749 	 * The solution is simple; test anything other than the first level
750 	 * (e.g. 1).
751 	 */
752 	test_level = current_level == max_level
753 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
754 		: max_level;
755 
756 	result = acpi_video_device_lcd_set_level(device, test_level);
757 	if (result)
758 		return result;
759 
760 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
761 	if (result)
762 		return result;
763 
764 	if (level != test_level) {
765 		/* buggy _BQC found, need to find out if it uses index */
766 		if (level < br->count) {
767 			if (br->flags._BCL_reversed)
768 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
769 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
770 				br->flags._BQC_use_index = 1;
771 		}
772 
773 		if (!br->flags._BQC_use_index)
774 			device->cap._BQC = device->cap._BCQ = 0;
775 	}
776 
777 	return 0;
778 }
779 
780 int acpi_video_get_levels(struct acpi_device *device,
781 			  struct acpi_video_device_brightness **dev_br,
782 			  int *pmax_level)
783 {
784 	union acpi_object *obj = NULL;
785 	int i, max_level = 0, count = 0, level_ac_battery = 0;
786 	union acpi_object *o;
787 	struct acpi_video_device_brightness *br = NULL;
788 	int result = 0;
789 	u32 value;
790 
791 	if (ACPI_FAILURE(acpi_video_device_lcd_query_levels(device->handle, &obj))) {
792 		acpi_handle_debug(device->handle,
793 				  "Could not query available LCD brightness level\n");
794 		result = -ENODEV;
795 		goto out;
796 	}
797 
798 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
799 		result = -EINVAL;
800 		goto out;
801 	}
802 
803 	br = kzalloc(sizeof(*br), GFP_KERNEL);
804 	if (!br) {
805 		result = -ENOMEM;
806 		goto out;
807 	}
808 
809 	/*
810 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
811 	 * in order to account for buggy BIOS which don't export the first two
812 	 * special levels (see below)
813 	 */
814 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
815 				   sizeof(*br->levels),
816 				   GFP_KERNEL);
817 	if (!br->levels) {
818 		result = -ENOMEM;
819 		goto out_free;
820 	}
821 
822 	for (i = 0; i < obj->package.count; i++) {
823 		o = (union acpi_object *)&obj->package.elements[i];
824 		if (o->type != ACPI_TYPE_INTEGER) {
825 			acpi_handle_info(device->handle, "Invalid data\n");
826 			continue;
827 		}
828 		value = (u32) o->integer.value;
829 		/* Skip duplicate entries */
830 		if (count > ACPI_VIDEO_FIRST_LEVEL
831 		    && br->levels[count - 1] == value)
832 			continue;
833 
834 		br->levels[count] = value;
835 
836 		if (br->levels[count] > max_level)
837 			max_level = br->levels[count];
838 		count++;
839 	}
840 
841 	/*
842 	 * some buggy BIOS don't export the levels
843 	 * when machine is on AC/Battery in _BCL package.
844 	 * In this case, the first two elements in _BCL packages
845 	 * are also supported brightness levels that OS should take care of.
846 	 */
847 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
848 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
849 			level_ac_battery++;
850 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
851 			level_ac_battery++;
852 	}
853 
854 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
855 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
856 		br->flags._BCL_no_ac_battery_levels = 1;
857 		for (i = (count - 1 + level_ac_battery);
858 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
859 			br->levels[i] = br->levels[i - level_ac_battery];
860 		count += level_ac_battery;
861 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
862 		acpi_handle_info(device->handle,
863 				 "Too many duplicates in _BCL package");
864 
865 	/* Check if the _BCL package is in a reversed order */
866 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
867 		br->flags._BCL_reversed = 1;
868 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
869 		     count - ACPI_VIDEO_FIRST_LEVEL,
870 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
871 		     acpi_video_cmp_level, NULL);
872 	} else if (max_level != br->levels[count - 1])
873 		acpi_handle_info(device->handle,
874 				 "Found unordered _BCL package");
875 
876 	br->count = count;
877 	*dev_br = br;
878 	if (pmax_level)
879 		*pmax_level = max_level;
880 
881 out:
882 	kfree(obj);
883 	return result;
884 out_free:
885 	kfree(br);
886 	goto out;
887 }
888 EXPORT_SYMBOL(acpi_video_get_levels);
889 
890 /*
891  *  Arg:
892  *	device	: video output device (LCD, CRT, ..)
893  *
894  *  Return Value:
895  *	Maximum brightness level
896  *
897  *  Allocate and initialize device->brightness.
898  */
899 
900 static int
901 acpi_video_init_brightness(struct acpi_video_device *device)
902 {
903 	int i, max_level = 0;
904 	unsigned long long level, level_old;
905 	struct acpi_video_device_brightness *br = NULL;
906 	int result;
907 
908 	result = acpi_video_get_levels(device->dev, &br, &max_level);
909 	if (result)
910 		return result;
911 	device->brightness = br;
912 
913 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
914 	br->curr = level = max_level;
915 
916 	if (!device->cap._BQC)
917 		goto set_level;
918 
919 	result = acpi_video_device_lcd_get_level_current(device,
920 							 &level_old, true);
921 	if (result)
922 		goto out_free_levels;
923 
924 	result = acpi_video_bqc_quirk(device, max_level, level_old);
925 	if (result)
926 		goto out_free_levels;
927 	/*
928 	 * cap._BQC may get cleared due to _BQC is found to be broken
929 	 * in acpi_video_bqc_quirk, so check again here.
930 	 */
931 	if (!device->cap._BQC)
932 		goto set_level;
933 
934 	level = acpi_video_bqc_value_to_level(device, level_old);
935 	/*
936 	 * On some buggy laptops, _BQC returns an uninitialized
937 	 * value when invoked for the first time, i.e.
938 	 * level_old is invalid (no matter whether it's a level
939 	 * or an index). Set the backlight to max_level in this case.
940 	 */
941 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
942 		if (level == br->levels[i])
943 			break;
944 	if (i == br->count || !level)
945 		level = max_level;
946 
947 set_level:
948 	result = acpi_video_device_lcd_set_level(device, level);
949 	if (result)
950 		goto out_free_levels;
951 
952 	acpi_handle_debug(device->dev->handle, "found %d brightness levels\n",
953 			  br->count - ACPI_VIDEO_FIRST_LEVEL);
954 
955 	return 0;
956 
957 out_free_levels:
958 	kfree(br->levels);
959 	kfree(br);
960 	device->brightness = NULL;
961 	return result;
962 }
963 
964 /*
965  *  Arg:
966  *	device	: video output device (LCD, CRT, ..)
967  *
968  *  Return Value:
969  *	None
970  *
971  *  Find out all required AML methods defined under the output
972  *  device.
973  */
974 
975 static void acpi_video_device_find_cap(struct acpi_video_device *device)
976 {
977 	if (acpi_has_method(device->dev->handle, "_ADR"))
978 		device->cap._ADR = 1;
979 	if (acpi_has_method(device->dev->handle, "_BCL"))
980 		device->cap._BCL = 1;
981 	if (acpi_has_method(device->dev->handle, "_BCM"))
982 		device->cap._BCM = 1;
983 	if (acpi_has_method(device->dev->handle, "_BQC")) {
984 		device->cap._BQC = 1;
985 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
986 		acpi_handle_info(device->dev->handle,
987 				 "_BCQ is used instead of _BQC\n");
988 		device->cap._BCQ = 1;
989 	}
990 
991 	if (acpi_has_method(device->dev->handle, "_DDC"))
992 		device->cap._DDC = 1;
993 }
994 
995 /*
996  *  Arg:
997  *	device	: video output device (VGA)
998  *
999  *  Return Value:
1000  *	None
1001  *
1002  *  Find out all required AML methods defined under the video bus device.
1003  */
1004 
1005 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1006 {
1007 	if (acpi_has_method(video->device->handle, "_DOS"))
1008 		video->cap._DOS = 1;
1009 	if (acpi_has_method(video->device->handle, "_DOD"))
1010 		video->cap._DOD = 1;
1011 	if (acpi_has_method(video->device->handle, "_ROM"))
1012 		video->cap._ROM = 1;
1013 	if (acpi_has_method(video->device->handle, "_GPD"))
1014 		video->cap._GPD = 1;
1015 	if (acpi_has_method(video->device->handle, "_SPD"))
1016 		video->cap._SPD = 1;
1017 	if (acpi_has_method(video->device->handle, "_VPO"))
1018 		video->cap._VPO = 1;
1019 }
1020 
1021 /*
1022  * Check whether the video bus device has required AML method to
1023  * support the desired features
1024  */
1025 
1026 static int acpi_video_bus_check(struct acpi_video_bus *video)
1027 {
1028 	acpi_status status = -ENOENT;
1029 	struct pci_dev *dev;
1030 
1031 	if (!video)
1032 		return -EINVAL;
1033 
1034 	dev = acpi_get_pci_dev(video->device->handle);
1035 	if (!dev)
1036 		return -ENODEV;
1037 	pci_dev_put(dev);
1038 
1039 	/*
1040 	 * Since there is no HID, CID and so on for VGA driver, we have
1041 	 * to check well known required nodes.
1042 	 */
1043 
1044 	/* Does this device support video switching? */
1045 	if (video->cap._DOS || video->cap._DOD) {
1046 		if (!video->cap._DOS) {
1047 			pr_info(FW_BUG "ACPI(%s) defines _DOD but not _DOS\n",
1048 				acpi_device_bid(video->device));
1049 		}
1050 		video->flags.multihead = 1;
1051 		status = 0;
1052 	}
1053 
1054 	/* Does this device support retrieving a video ROM? */
1055 	if (video->cap._ROM) {
1056 		video->flags.rom = 1;
1057 		status = 0;
1058 	}
1059 
1060 	/* Does this device support configuring which video device to POST? */
1061 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1062 		video->flags.post = 1;
1063 		status = 0;
1064 	}
1065 
1066 	return status;
1067 }
1068 
1069 /*
1070  * --------------------------------------------------------------------------
1071  *                               Driver Interface
1072  * --------------------------------------------------------------------------
1073  */
1074 
1075 /* device interface */
1076 static struct acpi_video_device_attrib *
1077 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1078 {
1079 	struct acpi_video_enumerated_device *ids;
1080 	int i;
1081 
1082 	for (i = 0; i < video->attached_count; i++) {
1083 		ids = &video->attached_array[i];
1084 		if ((ids->value.int_val & 0xffff) == device_id)
1085 			return &ids->value.attrib;
1086 	}
1087 
1088 	return NULL;
1089 }
1090 
1091 static int
1092 acpi_video_get_device_type(struct acpi_video_bus *video,
1093 			   unsigned long device_id)
1094 {
1095 	struct acpi_video_enumerated_device *ids;
1096 	int i;
1097 
1098 	for (i = 0; i < video->attached_count; i++) {
1099 		ids = &video->attached_array[i];
1100 		if ((ids->value.int_val & 0xffff) == device_id)
1101 			return ids->value.int_val;
1102 	}
1103 
1104 	return 0;
1105 }
1106 
1107 static int acpi_video_bus_get_one_device(struct acpi_device *device, void *arg)
1108 {
1109 	struct acpi_video_bus *video = arg;
1110 	struct acpi_video_device_attrib *attribute;
1111 	struct acpi_video_device *data;
1112 	unsigned long long device_id;
1113 	acpi_status status;
1114 	int device_type;
1115 
1116 	status = acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1117 	/* Skip devices without _ADR instead of failing. */
1118 	if (ACPI_FAILURE(status))
1119 		goto exit;
1120 
1121 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1122 	if (!data) {
1123 		dev_dbg(&device->dev, "Cannot attach\n");
1124 		return -ENOMEM;
1125 	}
1126 
1127 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1128 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1129 	device->driver_data = data;
1130 
1131 	data->device_id = device_id;
1132 	data->video = video;
1133 	data->dev = device;
1134 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1135 			  acpi_video_switch_brightness);
1136 
1137 	attribute = acpi_video_get_device_attr(video, device_id);
1138 
1139 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1140 		switch (attribute->display_type) {
1141 		case ACPI_VIDEO_DISPLAY_CRT:
1142 			data->flags.crt = 1;
1143 			break;
1144 		case ACPI_VIDEO_DISPLAY_TV:
1145 			data->flags.tvout = 1;
1146 			break;
1147 		case ACPI_VIDEO_DISPLAY_DVI:
1148 			data->flags.dvi = 1;
1149 			break;
1150 		case ACPI_VIDEO_DISPLAY_LCD:
1151 			data->flags.lcd = 1;
1152 			break;
1153 		default:
1154 			data->flags.unknown = 1;
1155 			break;
1156 		}
1157 		if (attribute->bios_can_detect)
1158 			data->flags.bios = 1;
1159 	} else {
1160 		/* Check for legacy IDs */
1161 		device_type = acpi_video_get_device_type(video, device_id);
1162 		/* Ignore bits 16 and 18-20 */
1163 		switch (device_type & 0xffe2ffff) {
1164 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1165 			data->flags.crt = 1;
1166 			break;
1167 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1168 			data->flags.lcd = 1;
1169 			break;
1170 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1171 			data->flags.tvout = 1;
1172 			break;
1173 		default:
1174 			data->flags.unknown = 1;
1175 		}
1176 	}
1177 
1178 	acpi_video_device_bind(video, data);
1179 	acpi_video_device_find_cap(data);
1180 
1181 	if (data->cap._BCM && data->cap._BCL)
1182 		may_report_brightness_keys = true;
1183 
1184 	mutex_lock(&video->device_list_lock);
1185 	list_add_tail(&data->entry, &video->video_device_list);
1186 	mutex_unlock(&video->device_list_lock);
1187 
1188 exit:
1189 	video->child_count++;
1190 	return 0;
1191 }
1192 
1193 /*
1194  *  Arg:
1195  *	video	: video bus device
1196  *
1197  *  Return:
1198  *	none
1199  *
1200  *  Enumerate the video device list of the video bus,
1201  *  bind the ids with the corresponding video devices
1202  *  under the video bus.
1203  */
1204 
1205 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1206 {
1207 	struct acpi_video_device *dev;
1208 
1209 	mutex_lock(&video->device_list_lock);
1210 
1211 	list_for_each_entry(dev, &video->video_device_list, entry)
1212 		acpi_video_device_bind(video, dev);
1213 
1214 	mutex_unlock(&video->device_list_lock);
1215 }
1216 
1217 /*
1218  *  Arg:
1219  *	video	: video bus device
1220  *	device	: video output device under the video
1221  *		bus
1222  *
1223  *  Return:
1224  *	none
1225  *
1226  *  Bind the ids with the corresponding video devices
1227  *  under the video bus.
1228  */
1229 
1230 static void
1231 acpi_video_device_bind(struct acpi_video_bus *video,
1232 		       struct acpi_video_device *device)
1233 {
1234 	struct acpi_video_enumerated_device *ids;
1235 	int i;
1236 
1237 	for (i = 0; i < video->attached_count; i++) {
1238 		ids = &video->attached_array[i];
1239 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1240 			ids->bind_info = device;
1241 			acpi_handle_debug(video->device->handle, "%s: %d\n",
1242 					  __func__, 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_FAILURE(status)) {
1295 		acpi_handle_info(video->device->handle,
1296 				 "_DOD evaluation failed: %s\n",
1297 				 acpi_format_exception(status));
1298 		return status;
1299 	}
1300 
1301 	dod = buffer.pointer;
1302 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1303 		acpi_handle_info(video->device->handle, "Invalid _DOD data\n");
1304 		status = -EFAULT;
1305 		goto out;
1306 	}
1307 
1308 	acpi_handle_debug(video->device->handle, "Found %d video heads in _DOD\n",
1309 			  dod->package.count);
1310 
1311 	active_list = kcalloc(1 + dod->package.count,
1312 			      sizeof(struct acpi_video_enumerated_device),
1313 			      GFP_KERNEL);
1314 	if (!active_list) {
1315 		status = -ENOMEM;
1316 		goto out;
1317 	}
1318 
1319 	count = 0;
1320 	for (i = 0; i < dod->package.count; i++) {
1321 		obj = &dod->package.elements[i];
1322 
1323 		if (obj->type != ACPI_TYPE_INTEGER) {
1324 			acpi_handle_info(video->device->handle,
1325 					 "Invalid _DOD data in element %d\n", i);
1326 			continue;
1327 		}
1328 
1329 		active_list[count].value.int_val = obj->integer.value;
1330 		active_list[count].bind_info = NULL;
1331 
1332 		acpi_handle_debug(video->device->handle,
1333 				  "_DOD element[%d] = %d\n", i,
1334 				  (int)obj->integer.value);
1335 
1336 		count++;
1337 	}
1338 
1339 	kfree(video->attached_array);
1340 
1341 	video->attached_array = active_list;
1342 	video->attached_count = count;
1343 
1344 out:
1345 	kfree(buffer.pointer);
1346 	return status;
1347 }
1348 
1349 static int
1350 acpi_video_get_next_level(struct acpi_video_device *device,
1351 			  u32 level_current, u32 event)
1352 {
1353 	int min, max, min_above, max_below, i, l, delta = 255;
1354 	max = max_below = 0;
1355 	min = min_above = 255;
1356 	/* Find closest level to level_current */
1357 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1358 		l = device->brightness->levels[i];
1359 		if (abs(l - level_current) < abs(delta)) {
1360 			delta = l - level_current;
1361 			if (!delta)
1362 				break;
1363 		}
1364 	}
1365 	/* Adjust level_current to closest available level */
1366 	level_current += delta;
1367 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1368 		l = device->brightness->levels[i];
1369 		if (l < min)
1370 			min = l;
1371 		if (l > max)
1372 			max = l;
1373 		if (l < min_above && l > level_current)
1374 			min_above = l;
1375 		if (l > max_below && l < level_current)
1376 			max_below = l;
1377 	}
1378 
1379 	switch (event) {
1380 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1381 		return (level_current < max) ? min_above : min;
1382 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1383 		return (level_current < max) ? min_above : max;
1384 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1385 		return (level_current > min) ? max_below : min;
1386 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1387 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1388 		return 0;
1389 	default:
1390 		return level_current;
1391 	}
1392 }
1393 
1394 static void
1395 acpi_video_switch_brightness(struct work_struct *work)
1396 {
1397 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1398 			     struct acpi_video_device, switch_brightness_work);
1399 	unsigned long long level_current, level_next;
1400 	int event = device->switch_brightness_event;
1401 	int result = -EINVAL;
1402 
1403 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1404 	if (!device->backlight)
1405 		return;
1406 
1407 	if (!device->brightness)
1408 		goto out;
1409 
1410 	result = acpi_video_device_lcd_get_level_current(device,
1411 							 &level_current,
1412 							 false);
1413 	if (result)
1414 		goto out;
1415 
1416 	level_next = acpi_video_get_next_level(device, level_current, event);
1417 
1418 	result = acpi_video_device_lcd_set_level(device, level_next);
1419 
1420 	if (!result)
1421 		backlight_force_update(device->backlight,
1422 				       BACKLIGHT_UPDATE_HOTKEY);
1423 
1424 out:
1425 	if (result)
1426 		acpi_handle_info(device->dev->handle,
1427 				 "Failed to switch brightness\n");
1428 }
1429 
1430 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1431 			void **edid)
1432 {
1433 	struct acpi_video_bus *video;
1434 	struct acpi_video_device *video_device;
1435 	union acpi_object *buffer = NULL;
1436 	acpi_status status;
1437 	int i, length;
1438 
1439 	if (!device || !acpi_driver_data(device))
1440 		return -EINVAL;
1441 
1442 	video = acpi_driver_data(device);
1443 
1444 	for (i = 0; i < video->attached_count; i++) {
1445 		video_device = video->attached_array[i].bind_info;
1446 		length = 256;
1447 
1448 		if (!video_device)
1449 			continue;
1450 
1451 		if (!video_device->cap._DDC)
1452 			continue;
1453 
1454 		if (type) {
1455 			switch (type) {
1456 			case ACPI_VIDEO_DISPLAY_CRT:
1457 				if (!video_device->flags.crt)
1458 					continue;
1459 				break;
1460 			case ACPI_VIDEO_DISPLAY_TV:
1461 				if (!video_device->flags.tvout)
1462 					continue;
1463 				break;
1464 			case ACPI_VIDEO_DISPLAY_DVI:
1465 				if (!video_device->flags.dvi)
1466 					continue;
1467 				break;
1468 			case ACPI_VIDEO_DISPLAY_LCD:
1469 				if (!video_device->flags.lcd)
1470 					continue;
1471 				break;
1472 			}
1473 		} else if (video_device->device_id != device_id) {
1474 			continue;
1475 		}
1476 
1477 		status = acpi_video_device_EDID(video_device, &buffer, length);
1478 
1479 		if (ACPI_FAILURE(status) || !buffer ||
1480 		    buffer->type != ACPI_TYPE_BUFFER) {
1481 			length = 128;
1482 			status = acpi_video_device_EDID(video_device, &buffer,
1483 							length);
1484 			if (ACPI_FAILURE(status) || !buffer ||
1485 			    buffer->type != ACPI_TYPE_BUFFER) {
1486 				continue;
1487 			}
1488 		}
1489 
1490 		*edid = buffer->buffer.pointer;
1491 		return length;
1492 	}
1493 
1494 	return -ENODEV;
1495 }
1496 EXPORT_SYMBOL(acpi_video_get_edid);
1497 
1498 static int
1499 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1500 			   struct acpi_device *device)
1501 {
1502 	/*
1503 	 * There are systems where video module known to work fine regardless
1504 	 * of broken _DOD and ignoring returned value here doesn't cause
1505 	 * any issues later.
1506 	 */
1507 	acpi_video_device_enumerate(video);
1508 
1509 	return acpi_dev_for_each_child(device, acpi_video_bus_get_one_device, video);
1510 }
1511 
1512 /* acpi_video interface */
1513 
1514 /*
1515  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1516  * perform any automatic brightness change on receiving a notification.
1517  */
1518 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1519 {
1520 	return acpi_video_bus_DOS(video, 0,
1521 				  acpi_osi_is_win8() ? 1 : 0);
1522 }
1523 
1524 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1525 {
1526 	return acpi_video_bus_DOS(video, 0,
1527 				  acpi_osi_is_win8() ? 0 : 1);
1528 }
1529 
1530 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1531 {
1532 	struct acpi_video_bus *video = acpi_driver_data(device);
1533 	struct input_dev *input;
1534 	int keycode = 0;
1535 
1536 	if (!video || !video->input)
1537 		return;
1538 
1539 	input = video->input;
1540 
1541 	switch (event) {
1542 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1543 					 * most likely via hotkey. */
1544 		keycode = KEY_SWITCHVIDEOMODE;
1545 		break;
1546 
1547 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1548 					 * connector. */
1549 		acpi_video_device_enumerate(video);
1550 		acpi_video_device_rebind(video);
1551 		keycode = KEY_SWITCHVIDEOMODE;
1552 		break;
1553 
1554 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1555 		keycode = KEY_SWITCHVIDEOMODE;
1556 		break;
1557 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1558 		keycode = KEY_VIDEO_NEXT;
1559 		break;
1560 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1561 		keycode = KEY_VIDEO_PREV;
1562 		break;
1563 
1564 	default:
1565 		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
1566 				  event);
1567 		break;
1568 	}
1569 
1570 	if (acpi_notifier_call_chain(device, event, 0))
1571 		/* Something vetoed the keypress. */
1572 		keycode = 0;
1573 
1574 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1575 		input_report_key(input, keycode, 1);
1576 		input_sync(input);
1577 		input_report_key(input, keycode, 0);
1578 		input_sync(input);
1579 	}
1580 }
1581 
1582 static void brightness_switch_event(struct acpi_video_device *video_device,
1583 				    u32 event)
1584 {
1585 	if (!brightness_switch_enabled)
1586 		return;
1587 
1588 	video_device->switch_brightness_event = event;
1589 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1590 }
1591 
1592 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1593 {
1594 	struct acpi_video_device *video_device = data;
1595 	struct acpi_device *device = NULL;
1596 	struct acpi_video_bus *bus;
1597 	struct input_dev *input;
1598 	int keycode = 0;
1599 
1600 	if (!video_device)
1601 		return;
1602 
1603 	device = video_device->dev;
1604 	bus = video_device->video;
1605 	input = bus->input;
1606 
1607 	if (hw_changes_brightness > 0) {
1608 		if (video_device->backlight)
1609 			backlight_force_update(video_device->backlight,
1610 					       BACKLIGHT_UPDATE_HOTKEY);
1611 		acpi_notifier_call_chain(device, event, 0);
1612 		return;
1613 	}
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_handle_debug(handle, "Unsupported event [0x%x]\n", event);
1638 		break;
1639 	}
1640 
1641 	if (keycode)
1642 		may_report_brightness_keys = true;
1643 
1644 	acpi_notifier_call_chain(device, event, 0);
1645 
1646 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1647 		input_report_key(input, keycode, 1);
1648 		input_sync(input);
1649 		input_report_key(input, keycode, 0);
1650 		input_sync(input);
1651 	}
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_POST_HIBERNATION:
1663 	case PM_POST_SUSPEND:
1664 	case PM_POST_RESTORE:
1665 		video = container_of(nb, struct acpi_video_bus, pm_nb);
1666 
1667 		dev_info(&video->device->dev, "Restoring backlight state\n");
1668 
1669 		for (i = 0; i < video->attached_count; i++) {
1670 			video_device = video->attached_array[i].bind_info;
1671 			if (video_device && video_device->brightness)
1672 				acpi_video_device_lcd_set_level(video_device,
1673 						video_device->brightness->curr);
1674 		}
1675 
1676 		return NOTIFY_OK;
1677 	}
1678 	return NOTIFY_DONE;
1679 }
1680 
1681 static acpi_status
1682 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1683 			void **return_value)
1684 {
1685 	struct acpi_device *device = context;
1686 	struct acpi_device *sibling;
1687 
1688 	if (handle == device->handle)
1689 		return AE_CTRL_TERMINATE;
1690 
1691 	sibling = acpi_fetch_acpi_dev(handle);
1692 	if (!sibling)
1693 		return AE_OK;
1694 
1695 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1696 			return AE_ALREADY_EXISTS;
1697 
1698 	return AE_OK;
1699 }
1700 
1701 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1702 {
1703 	struct backlight_properties props;
1704 	struct pci_dev *pdev;
1705 	acpi_handle acpi_parent;
1706 	struct device *parent = NULL;
1707 	int result;
1708 	static int count;
1709 	char *name;
1710 
1711 	result = acpi_video_init_brightness(device);
1712 	if (result)
1713 		return;
1714 
1715 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1716 	if (!name)
1717 		return;
1718 	count++;
1719 
1720 	acpi_get_parent(device->dev->handle, &acpi_parent);
1721 
1722 	pdev = acpi_get_pci_dev(acpi_parent);
1723 	if (pdev) {
1724 		parent = &pdev->dev;
1725 		pci_dev_put(pdev);
1726 	}
1727 
1728 	memset(&props, 0, sizeof(struct backlight_properties));
1729 	props.type = BACKLIGHT_FIRMWARE;
1730 	props.max_brightness =
1731 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1732 	device->backlight = backlight_device_register(name,
1733 						      parent,
1734 						      device,
1735 						      &acpi_backlight_ops,
1736 						      &props);
1737 	kfree(name);
1738 	if (IS_ERR(device->backlight)) {
1739 		device->backlight = NULL;
1740 		return;
1741 	}
1742 
1743 	/*
1744 	 * Save current brightness level in case we have to restore it
1745 	 * before acpi_video_device_lcd_set_level() is called next time.
1746 	 */
1747 	device->backlight->props.brightness =
1748 			acpi_video_get_brightness(device->backlight);
1749 
1750 	device->cooling_dev = thermal_cooling_device_register("LCD",
1751 				device->dev, &video_cooling_ops);
1752 	if (IS_ERR(device->cooling_dev)) {
1753 		/*
1754 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1755 		 * Also, why the hell we are returning early and not attempt to
1756 		 * register video output if cooling device registration failed?
1757 		 * -- dtor
1758 		 */
1759 		device->cooling_dev = NULL;
1760 		return;
1761 	}
1762 
1763 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1764 		 device->cooling_dev->id);
1765 	result = sysfs_create_link(&device->dev->dev.kobj,
1766 			&device->cooling_dev->device.kobj,
1767 			"thermal_cooling");
1768 	if (result)
1769 		pr_info("sysfs link creation failed\n");
1770 
1771 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1772 			&device->dev->dev.kobj, "device");
1773 	if (result)
1774 		pr_info("Reverse sysfs link creation failed\n");
1775 }
1776 
1777 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1778 {
1779 	struct acpi_video_device *dev;
1780 	union acpi_object *levels;
1781 
1782 	mutex_lock(&video->device_list_lock);
1783 	list_for_each_entry(dev, &video->video_device_list, entry) {
1784 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1785 			kfree(levels);
1786 	}
1787 	mutex_unlock(&video->device_list_lock);
1788 }
1789 
1790 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1791 {
1792 	/*
1793 	 * Do not create backlight device for video output
1794 	 * device that is not in the enumerated list.
1795 	 */
1796 	if (!acpi_video_device_in_dod(dev)) {
1797 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1798 		return false;
1799 	}
1800 
1801 	if (only_lcd)
1802 		return dev->flags.lcd;
1803 	return true;
1804 }
1805 
1806 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1807 {
1808 	struct acpi_video_device *dev;
1809 
1810 	if (video->backlight_registered)
1811 		return 0;
1812 
1813 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1814 		return 0;
1815 
1816 	mutex_lock(&video->device_list_lock);
1817 	list_for_each_entry(dev, &video->video_device_list, entry) {
1818 		if (acpi_video_should_register_backlight(dev))
1819 			acpi_video_dev_register_backlight(dev);
1820 	}
1821 	mutex_unlock(&video->device_list_lock);
1822 
1823 	video->backlight_registered = true;
1824 
1825 	video->pm_nb.notifier_call = acpi_video_resume;
1826 	video->pm_nb.priority = 0;
1827 	return register_pm_notifier(&video->pm_nb);
1828 }
1829 
1830 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1831 {
1832 	if (device->backlight) {
1833 		backlight_device_unregister(device->backlight);
1834 		device->backlight = NULL;
1835 	}
1836 	if (device->brightness) {
1837 		kfree(device->brightness->levels);
1838 		kfree(device->brightness);
1839 		device->brightness = NULL;
1840 	}
1841 	if (device->cooling_dev) {
1842 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1843 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1844 		thermal_cooling_device_unregister(device->cooling_dev);
1845 		device->cooling_dev = NULL;
1846 	}
1847 }
1848 
1849 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1850 {
1851 	struct acpi_video_device *dev;
1852 	int error;
1853 
1854 	if (!video->backlight_registered)
1855 		return 0;
1856 
1857 	error = unregister_pm_notifier(&video->pm_nb);
1858 
1859 	mutex_lock(&video->device_list_lock);
1860 	list_for_each_entry(dev, &video->video_device_list, entry)
1861 		acpi_video_dev_unregister_backlight(dev);
1862 	mutex_unlock(&video->device_list_lock);
1863 
1864 	video->backlight_registered = false;
1865 
1866 	return error;
1867 }
1868 
1869 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1870 {
1871 	acpi_status status;
1872 	struct acpi_device *adev = device->dev;
1873 
1874 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1875 					     acpi_video_device_notify, device);
1876 	if (ACPI_FAILURE(status))
1877 		dev_err(&adev->dev, "Error installing notify handler\n");
1878 	else
1879 		device->flags.notify = 1;
1880 }
1881 
1882 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1883 {
1884 	struct input_dev *input;
1885 	struct acpi_video_device *dev;
1886 	int error;
1887 
1888 	video->input = input = input_allocate_device();
1889 	if (!input) {
1890 		error = -ENOMEM;
1891 		goto out;
1892 	}
1893 
1894 	error = acpi_video_bus_start_devices(video);
1895 	if (error)
1896 		goto err_free_input;
1897 
1898 	snprintf(video->phys, sizeof(video->phys),
1899 			"%s/video/input0", acpi_device_hid(video->device));
1900 
1901 	input->name = acpi_device_name(video->device);
1902 	input->phys = video->phys;
1903 	input->id.bustype = BUS_HOST;
1904 	input->id.product = 0x06;
1905 	input->dev.parent = &video->device->dev;
1906 	input->evbit[0] = BIT(EV_KEY);
1907 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1908 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1909 	set_bit(KEY_VIDEO_PREV, input->keybit);
1910 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1911 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1912 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1913 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1914 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1915 
1916 	error = input_register_device(input);
1917 	if (error)
1918 		goto err_stop_dev;
1919 
1920 	mutex_lock(&video->device_list_lock);
1921 	list_for_each_entry(dev, &video->video_device_list, entry)
1922 		acpi_video_dev_add_notify_handler(dev);
1923 	mutex_unlock(&video->device_list_lock);
1924 
1925 	return 0;
1926 
1927 err_stop_dev:
1928 	acpi_video_bus_stop_devices(video);
1929 err_free_input:
1930 	input_free_device(input);
1931 	video->input = NULL;
1932 out:
1933 	return error;
1934 }
1935 
1936 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1937 {
1938 	if (dev->flags.notify) {
1939 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1940 					   acpi_video_device_notify);
1941 		dev->flags.notify = 0;
1942 	}
1943 }
1944 
1945 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1946 {
1947 	struct acpi_video_device *dev;
1948 
1949 	mutex_lock(&video->device_list_lock);
1950 	list_for_each_entry(dev, &video->video_device_list, entry)
1951 		acpi_video_dev_remove_notify_handler(dev);
1952 	mutex_unlock(&video->device_list_lock);
1953 
1954 	acpi_video_bus_stop_devices(video);
1955 	input_unregister_device(video->input);
1956 	video->input = NULL;
1957 }
1958 
1959 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1960 {
1961 	struct acpi_video_device *dev, *next;
1962 
1963 	mutex_lock(&video->device_list_lock);
1964 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1965 		list_del(&dev->entry);
1966 		kfree(dev);
1967 	}
1968 	mutex_unlock(&video->device_list_lock);
1969 
1970 	return 0;
1971 }
1972 
1973 static int instance;
1974 
1975 static int acpi_video_bus_add(struct acpi_device *device)
1976 {
1977 	struct acpi_video_bus *video;
1978 	bool auto_detect;
1979 	int error;
1980 	acpi_status status;
1981 
1982 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1983 				acpi_dev_parent(device)->handle, 1,
1984 				acpi_video_bus_match, NULL,
1985 				device, NULL);
1986 	if (status == AE_ALREADY_EXISTS) {
1987 		pr_info(FW_BUG
1988 			"Duplicate ACPI video bus devices for the"
1989 			" same VGA controller, please try module "
1990 			"parameter \"video.allow_duplicates=1\""
1991 			"if the current driver doesn't work.\n");
1992 		if (!allow_duplicates)
1993 			return -ENODEV;
1994 	}
1995 
1996 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1997 	if (!video)
1998 		return -ENOMEM;
1999 
2000 	/* a hack to fix the duplicate name "VID" problem on T61 */
2001 	if (!strcmp(device->pnp.bus_id, "VID")) {
2002 		if (instance)
2003 			device->pnp.bus_id[3] = '0' + instance;
2004 		instance++;
2005 	}
2006 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2007 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2008 		if (instance)
2009 			device->pnp.bus_id[3] = '0' + instance;
2010 		instance++;
2011 	}
2012 
2013 	video->device = device;
2014 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2015 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2016 	device->driver_data = video;
2017 
2018 	acpi_video_bus_find_cap(video);
2019 	error = acpi_video_bus_check(video);
2020 	if (error)
2021 		goto err_free_video;
2022 
2023 	mutex_init(&video->device_list_lock);
2024 	INIT_LIST_HEAD(&video->video_device_list);
2025 
2026 	error = acpi_video_bus_get_devices(video, device);
2027 	if (error)
2028 		goto err_put_video;
2029 
2030 	pr_info("%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2031 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2032 	       video->flags.multihead ? "yes" : "no",
2033 	       video->flags.rom ? "yes" : "no",
2034 	       video->flags.post ? "yes" : "no");
2035 	mutex_lock(&video_list_lock);
2036 	list_add_tail(&video->entry, &video_bus_head);
2037 	mutex_unlock(&video_list_lock);
2038 
2039 	/*
2040 	 * If backlight-type auto-detection is used then a native backlight may
2041 	 * show up later and this may change the result from video to native.
2042 	 * Therefor normally the userspace visible /sys/class/backlight device
2043 	 * gets registered separately by the GPU driver calling
2044 	 * acpi_video_register_backlight() when an internal panel is detected.
2045 	 * Register the backlight now when not using auto-detection, so that
2046 	 * when the kernel cmdline or DMI-quirks are used the backlight will
2047 	 * get registered even if acpi_video_register_backlight() is not called.
2048 	 */
2049 	acpi_video_run_bcl_for_osi(video);
2050 	if (__acpi_video_get_backlight_type(false, &auto_detect) == acpi_backlight_video &&
2051 	    !auto_detect)
2052 		acpi_video_bus_register_backlight(video);
2053 
2054 	acpi_video_bus_add_notify_handler(video);
2055 
2056 	return 0;
2057 
2058 err_put_video:
2059 	acpi_video_bus_put_devices(video);
2060 	kfree(video->attached_array);
2061 err_free_video:
2062 	kfree(video);
2063 	device->driver_data = NULL;
2064 
2065 	return error;
2066 }
2067 
2068 static void acpi_video_bus_remove(struct acpi_device *device)
2069 {
2070 	struct acpi_video_bus *video = NULL;
2071 
2072 
2073 	if (!device || !acpi_driver_data(device))
2074 		return;
2075 
2076 	video = acpi_driver_data(device);
2077 
2078 	mutex_lock(&video_list_lock);
2079 	list_del(&video->entry);
2080 	mutex_unlock(&video_list_lock);
2081 
2082 	acpi_video_bus_remove_notify_handler(video);
2083 	acpi_video_bus_unregister_backlight(video);
2084 	acpi_video_bus_put_devices(video);
2085 
2086 	kfree(video->attached_array);
2087 	kfree(video);
2088 }
2089 
2090 static int __init is_i740(struct pci_dev *dev)
2091 {
2092 	if (dev->device == 0x00D1)
2093 		return 1;
2094 	if (dev->device == 0x7000)
2095 		return 1;
2096 	return 0;
2097 }
2098 
2099 static int __init intel_opregion_present(void)
2100 {
2101 	int opregion = 0;
2102 	struct pci_dev *dev = NULL;
2103 	u32 address;
2104 
2105 	for_each_pci_dev(dev) {
2106 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2107 			continue;
2108 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2109 			continue;
2110 		/* We don't want to poke around undefined i740 registers */
2111 		if (is_i740(dev))
2112 			continue;
2113 		pci_read_config_dword(dev, 0xfc, &address);
2114 		if (!address)
2115 			continue;
2116 		opregion = 1;
2117 	}
2118 	return opregion;
2119 }
2120 
2121 /* Check if the chassis-type indicates there is no builtin LCD panel */
2122 static bool dmi_is_desktop(void)
2123 {
2124 	const char *chassis_type;
2125 	unsigned long type;
2126 
2127 	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2128 	if (!chassis_type)
2129 		return false;
2130 
2131 	if (kstrtoul(chassis_type, 10, &type) != 0)
2132 		return false;
2133 
2134 	switch (type) {
2135 	case 0x03: /* Desktop */
2136 	case 0x04: /* Low Profile Desktop */
2137 	case 0x05: /* Pizza Box */
2138 	case 0x06: /* Mini Tower */
2139 	case 0x07: /* Tower */
2140 	case 0x10: /* Lunch Box */
2141 	case 0x11: /* Main Server Chassis */
2142 		return true;
2143 	}
2144 
2145 	return false;
2146 }
2147 
2148 /*
2149  * We're seeing a lot of bogus backlight interfaces on newer machines
2150  * without a LCD such as desktops, servers and HDMI sticks. Checking the
2151  * lcd flag fixes this, enable this by default on any machines which are:
2152  * 1.  Win8 ready (where we also prefer the native backlight driver, so
2153  *     normally the acpi_video code should not register there anyways); *and*
2154  * 2.1 Report a desktop/server DMI chassis-type, or
2155  * 2.2 Are an ACPI-reduced-hardware platform (and thus won't use the EC for
2156        backlight control)
2157  */
2158 static bool should_check_lcd_flag(void)
2159 {
2160 	if (!acpi_osi_is_win8())
2161 		return false;
2162 
2163 	if (dmi_is_desktop())
2164 		return true;
2165 
2166 	if (acpi_reduced_hardware())
2167 		return true;
2168 
2169 	return false;
2170 }
2171 
2172 int acpi_video_register(void)
2173 {
2174 	int ret = 0;
2175 
2176 	mutex_lock(&register_count_mutex);
2177 	if (register_count) {
2178 		/*
2179 		 * if the function of acpi_video_register is already called,
2180 		 * don't register the acpi_video_bus again and return no error.
2181 		 */
2182 		goto leave;
2183 	}
2184 
2185 	if (only_lcd == -1)
2186 		only_lcd = should_check_lcd_flag();
2187 
2188 	dmi_check_system(video_dmi_table);
2189 
2190 	ret = acpi_bus_register_driver(&acpi_video_bus);
2191 	if (ret)
2192 		goto leave;
2193 
2194 	/*
2195 	 * When the acpi_video_bus is loaded successfully, increase
2196 	 * the counter reference.
2197 	 */
2198 	register_count = 1;
2199 
2200 leave:
2201 	mutex_unlock(&register_count_mutex);
2202 	return ret;
2203 }
2204 EXPORT_SYMBOL(acpi_video_register);
2205 
2206 void acpi_video_unregister(void)
2207 {
2208 	mutex_lock(&register_count_mutex);
2209 	if (register_count) {
2210 		acpi_bus_unregister_driver(&acpi_video_bus);
2211 		register_count = 0;
2212 		may_report_brightness_keys = false;
2213 	}
2214 	mutex_unlock(&register_count_mutex);
2215 }
2216 EXPORT_SYMBOL(acpi_video_unregister);
2217 
2218 void acpi_video_register_backlight(void)
2219 {
2220 	struct acpi_video_bus *video;
2221 
2222 	mutex_lock(&video_list_lock);
2223 	list_for_each_entry(video, &video_bus_head, entry)
2224 		acpi_video_bus_register_backlight(video);
2225 	mutex_unlock(&video_list_lock);
2226 }
2227 EXPORT_SYMBOL(acpi_video_register_backlight);
2228 
2229 bool acpi_video_handles_brightness_key_presses(void)
2230 {
2231 	return may_report_brightness_keys &&
2232 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2233 }
2234 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2235 
2236 /*
2237  * This is kind of nasty. Hardware using Intel chipsets may require
2238  * the video opregion code to be run first in order to initialise
2239  * state before any ACPI video calls are made. To handle this we defer
2240  * registration of the video class until the opregion code has run.
2241  */
2242 
2243 static int __init acpi_video_init(void)
2244 {
2245 	/*
2246 	 * Let the module load even if ACPI is disabled (e.g. due to
2247 	 * a broken BIOS) so that i915.ko can still be loaded on such
2248 	 * old systems without an AcpiOpRegion.
2249 	 *
2250 	 * acpi_video_register() will report -ENODEV later as well due
2251 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2252 	 */
2253 	if (acpi_disabled)
2254 		return 0;
2255 
2256 	if (intel_opregion_present())
2257 		return 0;
2258 
2259 	return acpi_video_register();
2260 }
2261 
2262 static void __exit acpi_video_exit(void)
2263 {
2264 	acpi_video_unregister();
2265 }
2266 
2267 module_init(acpi_video_init);
2268 module_exit(acpi_video_exit);
2269