2 * Copyright (C) 2008 SuSE Linux Products GmbH
3 * Thomas Renninger <trenn@suse.de>
5 * May be copied or modified under the terms of the GNU General Public License
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
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
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();
23 * Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B)
24 * are available, video.ko should be used to handle the device.
26 * Otherwise vendor specific drivers like thinkpad_acpi, asus-laptop,
27 * sony_acpi,... can take care about backlight brightness.
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.
36 #include <linux/export.h>
37 #include <linux/acpi.h>
38 #include <linux/dmi.h>
39 #include <linux/pci.h>
43 ACPI_MODULE_NAME("video");
44 #define _COMPONENT ACPI_VIDEO_COMPONENT
46 static long acpi_video_support
;
47 static bool acpi_video_caps_checked
;
50 acpi_backlight_cap_match(acpi_handle handle
, u32 level
, void *context
,
55 if (acpi_has_method(handle
, "_BCM") &&
56 acpi_has_method(handle
, "_BCL")) {
57 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "Found generic backlight "
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
;
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
77 long acpi_is_video_device(acpi_handle handle
)
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
;
85 /* Is this device able to retrieve a video ROM ? */
86 if (acpi_has_method(handle
, "_ROM"))
87 video_caps
|= ACPI_VIDEO_ROM_AVAILABLE
;
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
;
95 /* Only check for backlight functionality if one of the above hit. */
97 acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
,
98 ACPI_UINT32_MAX
, acpi_backlight_cap_match
, NULL
,
103 EXPORT_SYMBOL(acpi_is_video_device
);
106 find_video(acpi_handle handle
, u32 lvl
, void *context
, void **rv
)
110 struct acpi_device
*acpi_dev
;
112 const struct acpi_device_id video_ids
[] = {
116 if (acpi_bus_get_device(handle
, &acpi_dev
))
119 if (!acpi_match_device_ids(acpi_dev
, video_ids
)) {
120 dev
= acpi_get_pci_dev(handle
);
124 *cap
|= acpi_is_video_device(handle
);
129 /* Force to use vendor driver when the ACPI device is known to be
131 static int video_detect_force_vendor(const struct dmi_system_id
*d
)
133 acpi_video_support
|= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
;
137 static 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().
145 .callback
= video_detect_force_vendor
,
148 DMI_MATCH(DMI_SYS_VENDOR
, "SAMSUNG ELECTRONICS CO., LTD."),
149 DMI_MATCH(DMI_PRODUCT_NAME
, "X360"),
150 DMI_MATCH(DMI_BOARD_NAME
, "X360"),
154 .callback
= video_detect_force_vendor
,
155 .ident
= "Asus UL30VT",
157 DMI_MATCH(DMI_SYS_VENDOR
, "ASUSTeK Computer Inc."),
158 DMI_MATCH(DMI_PRODUCT_NAME
, "UL30VT"),
162 .callback
= video_detect_force_vendor
,
163 .ident
= "Asus UL30A",
165 DMI_MATCH(DMI_SYS_VENDOR
, "ASUSTeK Computer Inc."),
166 DMI_MATCH(DMI_PRODUCT_NAME
, "UL30A"),
173 * Returns the video capabilities of a specific ACPI graphics device
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.
179 long acpi_video_get_capabilities(acpi_handle graphics_handle
)
182 struct acpi_device
*tmp_dev
;
185 if (acpi_video_caps_checked
&& graphics_handle
== NULL
)
186 return acpi_video_support
;
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
,
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.:
199 * if (dmi_name_in_vendors("XY")) {
200 * acpi_video_support |=
201 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
205 dmi_check_system(video_detect_dmi_table
);
207 status
= acpi_bus_get_device(graphics_handle
, &tmp_dev
);
208 if (ACPI_FAILURE(status
)) {
209 ACPI_EXCEPTION((AE_INFO
, status
, "Invalid device"));
212 acpi_walk_namespace(ACPI_TYPE_DEVICE
, graphics_handle
,
213 ACPI_UINT32_MAX
, find_video
, NULL
,
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
) : ""));
222 EXPORT_SYMBOL(acpi_video_get_capabilities
);
224 static void acpi_video_caps_check(void)
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
230 if (!acpi_video_caps_checked
)
231 acpi_video_get_capabilities(NULL
);
234 bool acpi_osi_is_win8(void)
236 return acpi_gbl_osi_data
>= ACPI_OSI_WIN_8
;
238 EXPORT_SYMBOL(acpi_osi_is_win8
);
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
246 void acpi_video_dmi_promote_vendor(void)
248 acpi_video_caps_check();
249 acpi_video_support
|= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
;
251 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor
);
253 /* To be called when a driver who previously promoted the vendor
255 void acpi_video_dmi_demote_vendor(void)
257 acpi_video_caps_check();
258 acpi_video_support
&= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
;
260 EXPORT_SYMBOL(acpi_video_dmi_demote_vendor
);
262 /* Returns true if video.ko can do backlight switching */
263 int acpi_video_backlight_support(void)
265 acpi_video_caps_check();
267 /* First check for boot param -> highest prio */
268 if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR
)
270 else if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO
)
273 /* Then check for DMI blacklist -> second highest prio */
274 if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
)
276 else if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_DMI_VIDEO
)
279 /* Then go the default way */
280 return acpi_video_support
& ACPI_VIDEO_BACKLIGHT
;
282 EXPORT_SYMBOL(acpi_video_backlight_support
);
285 * Use acpi_backlight=vendor/video to force that backlight switching
286 * is processed by vendor specific acpi drivers or video.ko driver.
288 static int __init
acpi_backlight(char *str
)
290 if (str
== NULL
|| *str
== '\0')
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
;
302 __setup("acpi_backlight=", acpi_backlight
);