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 (or display output) 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_acpi,
27 * sony_acpi,... can take care about backlight brightness and display output
30 * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
31 * this file will not be compiled, acpi_video_get_capabilities() and
32 * acpi_video_backlight_support() will always return 0 and vendor specific
33 * drivers always can handle backlight.
37 #include <linux/acpi.h>
38 #include <linux/dmi.h>
39 #include <linux/pci.h>
41 #define PREFIX "ACPI: "
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
,
56 if (ACPI_SUCCESS(acpi_get_handle(handle
, "_BCM", &h_dummy
)) &&
57 ACPI_SUCCESS(acpi_get_handle(handle
, "_BCL", &h_dummy
))) {
58 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "Found generic backlight "
60 *cap
|= ACPI_VIDEO_BACKLIGHT
;
61 if (ACPI_FAILURE(acpi_get_handle(handle
, "_BQC", &h_dummy
)))
62 printk(KERN_WARNING FW_BUG PREFIX
"ACPI brightness "
63 "control misses _BQC function\n");
64 /* We have backlight support, no need to scan further */
65 return AE_CTRL_TERMINATE
;
70 /* Returns true if the device is a video device which can be handled by
72 * The device will get a Linux specific CID added in scan.c to
73 * identify the device as an ACPI graphics device
74 * Be aware that the graphics device may not be physically present
75 * Use acpi_video_get_capabilities() to detect general ACPI video
76 * capabilities of present cards
78 long acpi_is_video_device(struct acpi_device
*device
)
86 /* Does this device able to support video switching ? */
87 if (ACPI_SUCCESS(acpi_get_handle(device
->handle
, "_DOD", &h_dummy
)) &&
88 ACPI_SUCCESS(acpi_get_handle(device
->handle
, "_DOS", &h_dummy
)))
89 video_caps
|= ACPI_VIDEO_OUTPUT_SWITCHING
;
91 /* Does this device able to retrieve a video ROM ? */
92 if (ACPI_SUCCESS(acpi_get_handle(device
->handle
, "_ROM", &h_dummy
)))
93 video_caps
|= ACPI_VIDEO_ROM_AVAILABLE
;
95 /* Does this device able to configure which video head to be POSTed ? */
96 if (ACPI_SUCCESS(acpi_get_handle(device
->handle
, "_VPO", &h_dummy
)) &&
97 ACPI_SUCCESS(acpi_get_handle(device
->handle
, "_GPD", &h_dummy
)) &&
98 ACPI_SUCCESS(acpi_get_handle(device
->handle
, "_SPD", &h_dummy
)))
99 video_caps
|= ACPI_VIDEO_DEVICE_POSTING
;
101 /* Only check for backlight functionality if one of the above hit. */
103 acpi_walk_namespace(ACPI_TYPE_DEVICE
, device
->handle
,
104 ACPI_UINT32_MAX
, acpi_backlight_cap_match
,
109 EXPORT_SYMBOL(acpi_is_video_device
);
112 find_video(acpi_handle handle
, u32 lvl
, void *context
, void **rv
)
116 struct acpi_device
*acpi_dev
;
118 const struct acpi_device_id video_ids
[] = {
122 if (acpi_bus_get_device(handle
, &acpi_dev
))
125 if (!acpi_match_device_ids(acpi_dev
, video_ids
)) {
126 dev
= acpi_get_pci_dev(handle
);
130 *cap
|= acpi_is_video_device(acpi_dev
);
136 * Returns the video capabilities of a specific ACPI graphics device
138 * if NULL is passed as argument all ACPI devices are enumerated and
139 * all graphics capabilities of physically present devices are
140 * summerized and returned. This is cached and done only once.
142 long acpi_video_get_capabilities(acpi_handle graphics_handle
)
145 struct acpi_device
*tmp_dev
;
148 if (acpi_video_caps_checked
&& graphics_handle
== NULL
)
149 return acpi_video_support
;
151 if (!graphics_handle
) {
152 /* Only do the global walk through all graphics devices once */
153 acpi_walk_namespace(ACPI_TYPE_DEVICE
, ACPI_ROOT_OBJECT
,
154 ACPI_UINT32_MAX
, find_video
,
156 /* There might be boot param flags set already... */
157 acpi_video_support
|= caps
;
158 acpi_video_caps_checked
= 1;
159 /* Add blacklists here. Be careful to use the right *DMI* bits
160 * to still be able to override logic via boot params, e.g.:
162 * if (dmi_name_in_vendors("XY")) {
163 * acpi_video_support |=
164 * ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR;
165 * acpi_video_support |=
166 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
170 status
= acpi_bus_get_device(graphics_handle
, &tmp_dev
);
171 if (ACPI_FAILURE(status
)) {
172 ACPI_EXCEPTION((AE_INFO
, status
, "Invalid device"));
175 acpi_walk_namespace(ACPI_TYPE_DEVICE
, graphics_handle
,
176 ACPI_UINT32_MAX
, find_video
,
179 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "We have 0x%lX video support %s %s\n",
180 graphics_handle
? caps
: acpi_video_support
,
181 graphics_handle
? "on device " : "in general",
182 graphics_handle
? acpi_device_bid(tmp_dev
) : ""));
185 EXPORT_SYMBOL(acpi_video_get_capabilities
);
187 /* Returns true if video.ko can do backlight switching */
188 int acpi_video_backlight_support(void)
191 * We must check whether the ACPI graphics device is physically plugged
192 * in. Therefore this must be called after binding PCI and ACPI devices
194 if (!acpi_video_caps_checked
)
195 acpi_video_get_capabilities(NULL
);
197 /* First check for boot param -> highest prio */
198 if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR
)
200 else if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO
)
203 /* Then check for DMI blacklist -> second highest prio */
204 if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_DMI_VENDOR
)
206 else if (acpi_video_support
& ACPI_VIDEO_BACKLIGHT_DMI_VIDEO
)
209 /* Then go the default way */
210 return acpi_video_support
& ACPI_VIDEO_BACKLIGHT
;
212 EXPORT_SYMBOL(acpi_video_backlight_support
);
215 * Returns true if video.ko can do display output switching.
216 * This does not work well/at all with binary graphics drivers
217 * which disable system io ranges and do it on their own.
219 int acpi_video_display_switch_support(void)
221 if (!acpi_video_caps_checked
)
222 acpi_video_get_capabilities(NULL
);
224 if (acpi_video_support
& ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR
)
226 else if (acpi_video_support
& ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO
)
229 if (acpi_video_support
& ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR
)
231 else if (acpi_video_support
& ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO
)
234 return acpi_video_support
& ACPI_VIDEO_OUTPUT_SWITCHING
;
236 EXPORT_SYMBOL(acpi_video_display_switch_support
);
239 * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video
240 * To force that backlight or display output switching is processed by vendor
241 * specific acpi drivers or video.ko driver.
243 static int __init
acpi_backlight(char *str
)
245 if (str
== NULL
|| *str
== '\0')
248 if (!strcmp("vendor", str
))
249 acpi_video_support
|=
250 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR
;
251 if (!strcmp("video", str
))
252 acpi_video_support
|=
253 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO
;
257 __setup("acpi_backlight=", acpi_backlight
);
259 static int __init
acpi_display_output(char *str
)
261 if (str
== NULL
|| *str
== '\0')
264 if (!strcmp("vendor", str
))
265 acpi_video_support
|=
266 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR
;
267 if (!strcmp("video", str
))
268 acpi_video_support
|=
269 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO
;
273 __setup("acpi_display_output=", acpi_display_output
);