1/*
2 *  Copyright (C) 2008       SuSE Linux Products GmbH
3 *                           Thomas Renninger <trenn@suse.de>
4 *
5 *  May be copied or modified under the terms of the GNU General Public License
6 *
7 * video_detect.c:
8 * Provides acpi_is_video_device() for early scanning of ACPI devices in scan.c
9 * There a Linux specific (Spec does not provide a HID for video devices) is
10 * assigned
11 *
12 * After PCI devices are glued with ACPI devices
13 * acpi_get_pci_dev() can be called to identify ACPI graphics
14 * devices for which a real graphics card is plugged in
15 *
16 * Now acpi_video_get_capabilities() can be called to check which
17 * capabilities the graphics cards plugged in support. The check for general
18 * video capabilities will be triggered by the first caller of
19 * acpi_video_get_capabilities(NULL); which will happen when the first
20 * backlight switching supporting driver calls:
21 * acpi_video_backlight_support();
22 *
23 * Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B)
24 * are available, video.ko should be used to handle the device.
25 *
26 * Otherwise vendor specific drivers like thinkpad_acpi, asus-laptop,
27 * sony_acpi,... can take care about backlight brightness.
28 *
29 * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
30 * this file will not be compiled, acpi_video_get_capabilities() and
31 * acpi_video_backlight_support() will always return 0 and vendor specific
32 * drivers always can handle backlight.
33 *
34 */
35
36#include <linux/export.h>
37#include <linux/acpi.h>
38#include <linux/dmi.h>
39#include <linux/pci.h>
40
41#include "internal.h"
42
43ACPI_MODULE_NAME("video");
44#define _COMPONENT		ACPI_VIDEO_COMPONENT
45
46static long acpi_video_support;
47static bool acpi_video_caps_checked;
48
49static acpi_status
50acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
51			  void **return_value)
52{
53	long *cap = context;
54
55	if (acpi_has_method(handle, "_BCM") &&
56	    acpi_has_method(handle, "_BCL")) {
57		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
58				  "support\n"));
59		*cap |= ACPI_VIDEO_BACKLIGHT;
60		if (!acpi_has_method(handle, "_BQC"))
61			printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
62				"cannot determine initial brightness\n");
63		/* We have backlight support, no need to scan further */
64		return AE_CTRL_TERMINATE;
65	}
66	return 0;
67}
68
69/* Returns true if the ACPI object is a video device which can be
70 * handled by video.ko.
71 * The device will get a Linux specific CID added in scan.c to
72 * identify the device as an ACPI graphics device
73 * Be aware that the graphics device may not be physically present
74 * Use acpi_video_get_capabilities() to detect general ACPI video
75 * capabilities of present cards
76 */
77long acpi_is_video_device(acpi_handle handle)
78{
79	long video_caps = 0;
80
81	/* Is this device able to support video switching ? */
82	if (acpi_has_method(handle, "_DOD") || acpi_has_method(handle, "_DOS"))
83		video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
84
85	/* Is this device able to retrieve a video ROM ? */
86	if (acpi_has_method(handle, "_ROM"))
87		video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
88
89	/* Is this device able to configure which video head to be POSTed ? */
90	if (acpi_has_method(handle, "_VPO") &&
91	    acpi_has_method(handle, "_GPD") &&
92	    acpi_has_method(handle, "_SPD"))
93		video_caps |= ACPI_VIDEO_DEVICE_POSTING;
94
95	/* Only check for backlight functionality if one of the above hit. */
96	if (video_caps)
97		acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
98				    ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
99				    &video_caps, NULL);
100
101	return video_caps;
102}
103EXPORT_SYMBOL(acpi_is_video_device);
104
105static acpi_status
106find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
107{
108	long *cap = context;
109	struct pci_dev *dev;
110	struct acpi_device *acpi_dev;
111
112	const struct acpi_device_id video_ids[] = {
113		{ACPI_VIDEO_HID, 0},
114		{"", 0},
115	};
116	if (acpi_bus_get_device(handle, &acpi_dev))
117		return AE_OK;
118
119	if (!acpi_match_device_ids(acpi_dev, video_ids)) {
120		dev = acpi_get_pci_dev(handle);
121		if (!dev)
122			return AE_OK;
123		pci_dev_put(dev);
124		*cap |= acpi_is_video_device(handle);
125	}
126	return AE_OK;
127}
128
129/* Force to use vendor driver when the ACPI device is known to be
130 * buggy */
131static int video_detect_force_vendor(const struct dmi_system_id *d)
132{
133	acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
134	return 0;
135}
136
137static struct dmi_system_id video_detect_dmi_table[] = {
138	/* On Samsung X360, the BIOS will set a flag (VDRV) if generic
139	 * ACPI backlight device is used. This flag will definitively break
140	 * the backlight interface (even the vendor interface) untill next
141	 * reboot. It's why we should prevent video.ko from being used here
142	 * and we can't rely on a later call to acpi_video_unregister().
143	 */
144	{
145	 .callback = video_detect_force_vendor,
146	 .ident = "X360",
147	 .matches = {
148		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
149		DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
150		DMI_MATCH(DMI_BOARD_NAME, "X360"),
151		},
152	},
153	{
154	.callback = video_detect_force_vendor,
155	.ident = "Asus UL30VT",
156	.matches = {
157		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
158		DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
159		},
160	},
161	{
162	.callback = video_detect_force_vendor,
163	.ident = "Asus UL30A",
164	.matches = {
165		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
166		DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"),
167		},
168	},
169	{ },
170};
171
172/*
173 * Returns the video capabilities of a specific ACPI graphics device
174 *
175 * if NULL is passed as argument all ACPI devices are enumerated and
176 * all graphics capabilities of physically present devices are
177 * summarized and returned. This is cached and done only once.
178 */
179long acpi_video_get_capabilities(acpi_handle graphics_handle)
180{
181	long caps = 0;
182	struct acpi_device *tmp_dev;
183	acpi_status status;
184
185	if (acpi_video_caps_checked && graphics_handle == NULL)
186		return acpi_video_support;
187
188	if (!graphics_handle) {
189		/* Only do the global walk through all graphics devices once */
190		acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
191				    ACPI_UINT32_MAX, find_video, NULL,
192				    &caps, NULL);
193		/* There might be boot param flags set already... */
194		acpi_video_support |= caps;
195		acpi_video_caps_checked = 1;
196		/* Add blacklists here. Be careful to use the right *DMI* bits
197		 * to still be able to override logic via boot params, e.g.:
198		 *
199		 *   if (dmi_name_in_vendors("XY")) {
200		 *	acpi_video_support |=
201		 *		ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
202		 *}
203		 */
204
205		dmi_check_system(video_detect_dmi_table);
206	} else {
207		status = acpi_bus_get_device(graphics_handle, &tmp_dev);
208		if (ACPI_FAILURE(status)) {
209			ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
210			return 0;
211		}
212		acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
213				    ACPI_UINT32_MAX, find_video, NULL,
214				    &caps, NULL);
215	}
216	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
217			  graphics_handle ? caps : acpi_video_support,
218			  graphics_handle ? "on device " : "in general",
219			  graphics_handle ? acpi_device_bid(tmp_dev) : ""));
220	return caps;
221}
222EXPORT_SYMBOL(acpi_video_get_capabilities);
223
224static void acpi_video_caps_check(void)
225{
226	/*
227	 * We must check whether the ACPI graphics device is physically plugged
228	 * in. Therefore this must be called after binding PCI and ACPI devices
229	 */
230	if (!acpi_video_caps_checked)
231		acpi_video_get_capabilities(NULL);
232}
233
234bool acpi_osi_is_win8(void)
235{
236	return acpi_gbl_osi_data >= ACPI_OSI_WIN_8;
237}
238EXPORT_SYMBOL(acpi_osi_is_win8);
239
240/* Promote the vendor interface instead of the generic video module.
241 * This function allow DMI blacklists to be implemented by externals
242 * platform drivers instead of putting a big blacklist in video_detect.c
243 * After calling this function you will probably want to call
244 * acpi_video_unregister() to make sure the video module is not loaded
245 */
246void acpi_video_dmi_promote_vendor(void)
247{
248	acpi_video_caps_check();
249	acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
250}
251EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
252
253/* To be called when a driver who previously promoted the vendor
254 * interface */
255void acpi_video_dmi_demote_vendor(void)
256{
257	acpi_video_caps_check();
258	acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
259}
260EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
261
262/* Returns true if video.ko can do backlight switching */
263int acpi_video_backlight_support(void)
264{
265	acpi_video_caps_check();
266
267	/* First check for boot param -> highest prio */
268	if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
269		return 0;
270	else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
271		return 1;
272
273	/* Then check for DMI blacklist -> second highest prio */
274	if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
275		return 0;
276	else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
277		return 1;
278
279	/* Then go the default way */
280	return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
281}
282EXPORT_SYMBOL(acpi_video_backlight_support);
283
284/*
285 * Use acpi_backlight=vendor/video to force that backlight switching
286 * is processed by vendor specific acpi drivers or video.ko driver.
287 */
288static int __init acpi_backlight(char *str)
289{
290	if (str == NULL || *str == '\0')
291		return 1;
292	else {
293		if (!strcmp("vendor", str))
294			acpi_video_support |=
295				ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
296		if (!strcmp("video", str))
297			acpi_video_support |=
298				ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
299	}
300	return 1;
301}
302__setup("acpi_backlight=", acpi_backlight);
303