Merge branch 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / acpi / video_detect.c
blob5af3479714f6dbd81268ef482603865258c4ee71
1 /*
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
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
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_acpi,
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/acpi.h>
37 #include <linux/dmi.h>
38 #include <linux/pci.h>
40 #define PREFIX "ACPI: "
42 ACPI_MODULE_NAME("video");
43 #define _COMPONENT ACPI_VIDEO_COMPONENT
45 static long acpi_video_support;
46 static bool acpi_video_caps_checked;
48 static acpi_status
49 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
50 void **retyurn_value)
52 long *cap = context;
53 acpi_handle h_dummy;
55 if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) &&
56 ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) {
57 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
58 "support\n"));
59 *cap |= ACPI_VIDEO_BACKLIGHT;
60 if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy)))
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;
66 return 0;
69 /* Returns true if the device is a video device which can be handled by
70 * 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(struct acpi_device *device)
79 acpi_handle h_dummy;
80 long video_caps = 0;
82 if (!device)
83 return 0;
85 /* Is this device able to support video switching ? */
86 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) ||
87 ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy)))
88 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
90 /* Is this device able to retrieve a video ROM ? */
91 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy)))
92 video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
94 /* Is this device able to configure which video head to be POSTed ? */
95 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) &&
96 ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) &&
97 ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy)))
98 video_caps |= ACPI_VIDEO_DEVICE_POSTING;
100 /* Only check for backlight functionality if one of the above hit. */
101 if (video_caps)
102 acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle,
103 ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
104 &video_caps, NULL);
106 return video_caps;
108 EXPORT_SYMBOL(acpi_is_video_device);
110 static acpi_status
111 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
113 long *cap = context;
114 struct pci_dev *dev;
115 struct acpi_device *acpi_dev;
117 const struct acpi_device_id video_ids[] = {
118 {ACPI_VIDEO_HID, 0},
119 {"", 0},
121 if (acpi_bus_get_device(handle, &acpi_dev))
122 return AE_OK;
124 if (!acpi_match_device_ids(acpi_dev, video_ids)) {
125 dev = acpi_get_pci_dev(handle);
126 if (!dev)
127 return AE_OK;
128 pci_dev_put(dev);
129 *cap |= acpi_is_video_device(acpi_dev);
131 return AE_OK;
135 * Returns the video capabilities of a specific ACPI graphics device
137 * if NULL is passed as argument all ACPI devices are enumerated and
138 * all graphics capabilities of physically present devices are
139 * summarized and returned. This is cached and done only once.
141 long acpi_video_get_capabilities(acpi_handle graphics_handle)
143 long caps = 0;
144 struct acpi_device *tmp_dev;
145 acpi_status status;
147 if (acpi_video_caps_checked && graphics_handle == NULL)
148 return acpi_video_support;
150 if (!graphics_handle) {
151 /* Only do the global walk through all graphics devices once */
152 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
153 ACPI_UINT32_MAX, find_video, NULL,
154 &caps, NULL);
155 /* There might be boot param flags set already... */
156 acpi_video_support |= caps;
157 acpi_video_caps_checked = 1;
158 /* Add blacklists here. Be careful to use the right *DMI* bits
159 * to still be able to override logic via boot params, e.g.:
161 * if (dmi_name_in_vendors("XY")) {
162 * acpi_video_support |=
163 * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
166 } else {
167 status = acpi_bus_get_device(graphics_handle, &tmp_dev);
168 if (ACPI_FAILURE(status)) {
169 ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
170 return 0;
172 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
173 ACPI_UINT32_MAX, find_video, NULL,
174 &caps, NULL);
176 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
177 graphics_handle ? caps : acpi_video_support,
178 graphics_handle ? "on device " : "in general",
179 graphics_handle ? acpi_device_bid(tmp_dev) : ""));
180 return caps;
182 EXPORT_SYMBOL(acpi_video_get_capabilities);
184 /* Returns true if video.ko can do backlight switching */
185 int acpi_video_backlight_support(void)
188 * We must check whether the ACPI graphics device is physically plugged
189 * in. Therefore this must be called after binding PCI and ACPI devices
191 if (!acpi_video_caps_checked)
192 acpi_video_get_capabilities(NULL);
194 /* First check for boot param -> highest prio */
195 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
196 return 0;
197 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
198 return 1;
200 /* Then check for DMI blacklist -> second highest prio */
201 if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
202 return 0;
203 else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
204 return 1;
206 /* Then go the default way */
207 return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
209 EXPORT_SYMBOL(acpi_video_backlight_support);
212 * Use acpi_backlight=vendor/video to force that backlight switching
213 * is processed by vendor specific acpi drivers or video.ko driver.
215 static int __init acpi_backlight(char *str)
217 if (str == NULL || *str == '\0')
218 return 1;
219 else {
220 if (!strcmp("vendor", str))
221 acpi_video_support |=
222 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
223 if (!strcmp("video", str))
224 acpi_video_support |=
225 ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
227 return 1;
229 __setup("acpi_backlight=", acpi_backlight);