ACPI video: add a warning message if _BQC is not found
[linux-3.10.git] / drivers / acpi / video_detect.c
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  * assinged
11  *
12  * After PCI devices are glued with ACPI devices
13  * acpi_get_physical_pci_device() 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 (or display output) 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_acpi,
27  * sony_acpi,... can take care about backlight brightness and display output
28  * switching.
29  *
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.
34  *
35  */
36
37 #include <linux/acpi.h>
38 #include <linux/dmi.h>
39
40 ACPI_MODULE_NAME("video");
41 #define _COMPONENT              ACPI_VIDEO_COMPONENT
42
43 static long acpi_video_support;
44 static bool acpi_video_caps_checked;
45
46 static acpi_status
47 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
48                           void **retyurn_value)
49 {
50         long *cap = context;
51         acpi_handle h_dummy;
52
53         if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) &&
54             ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) {
55                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
56                                   "support\n"));
57                 *cap |= ACPI_VIDEO_BACKLIGHT;
58                 if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy)))
59                         printk(KERN_WARNING FW_BUG PREFIX "ACPI brightness "
60                                         "control misses _BQC function\n");
61                 /* We have backlight support, no need to scan further */
62                 return AE_CTRL_TERMINATE;
63         }
64         return 0;
65 }
66
67 /* Returns true if the device is a video device which can be handled by
68  * video.ko.
69  * The device will get a Linux specific CID added in scan.c to
70  * identify the device as an ACPI graphics device
71  * Be aware that the graphics device may not be physically present
72  * Use acpi_video_get_capabilities() to detect general ACPI video
73  * capabilities of present cards
74  */
75 long acpi_is_video_device(struct acpi_device *device)
76 {
77         acpi_handle h_dummy;
78         long video_caps = 0;
79
80         if (!device)
81                 return 0;
82
83         /* Does this device able to support video switching ? */
84         if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) &&
85             ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy)))
86                 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
87
88         /* Does this device able to retrieve a video ROM ? */
89         if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy)))
90                 video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
91
92         /* Does this device able to configure which video head to be POSTed ? */
93         if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) &&
94             ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) &&
95             ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy)))
96                 video_caps |= ACPI_VIDEO_DEVICE_POSTING;
97
98         /* Only check for backlight functionality if one of the above hit. */
99         if (video_caps)
100                 acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle,
101                                     ACPI_UINT32_MAX, acpi_backlight_cap_match,
102                                     &video_caps, NULL);
103
104         return video_caps;
105 }
106 EXPORT_SYMBOL(acpi_is_video_device);
107
108 static acpi_status
109 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
110 {
111         long *cap = context;
112         struct device *dev;
113         struct acpi_device *acpi_dev;
114
115         const struct acpi_device_id video_ids[] = {
116                 {ACPI_VIDEO_HID, 0},
117                 {"", 0},
118         };
119         if (acpi_bus_get_device(handle, &acpi_dev))
120                 return AE_OK;
121
122         if (!acpi_match_device_ids(acpi_dev, video_ids)) {
123                 dev = acpi_get_physical_pci_device(handle);
124                 if (!dev)
125                         return AE_OK;
126                 put_device(dev);
127                 *cap |= acpi_is_video_device(acpi_dev);
128         }
129         return AE_OK;
130 }
131
132 /*
133  * Returns the video capabilities of a specific ACPI graphics device
134  *
135  * if NULL is passed as argument all ACPI devices are enumerated and
136  * all graphics capabilities of physically present devices are
137  * summerized and returned. This is cached and done only once.
138  */
139 long acpi_video_get_capabilities(acpi_handle graphics_handle)
140 {
141         long caps = 0;
142         struct acpi_device *tmp_dev;
143         acpi_status status;
144
145         if (acpi_video_caps_checked && graphics_handle == NULL)
146                 return acpi_video_support;
147
148         if (!graphics_handle) {
149                 /* Only do the global walk through all graphics devices once */
150                 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
151                                     ACPI_UINT32_MAX, find_video,
152                                     &caps, NULL);
153                 /* There might be boot param flags set already... */
154                 acpi_video_support |= caps;
155                 acpi_video_caps_checked = 1;
156                 /* Add blacklists here. Be careful to use the right *DMI* bits
157                  * to still be able to override logic via boot params, e.g.:
158                  *
159                  *   if (dmi_name_in_vendors("XY")) {
160                  *      acpi_video_support |=
161                  *              ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR;
162                  *      acpi_video_support |=
163                  *              ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
164                  *}
165                  */
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;
171                 }
172                 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
173                                     ACPI_UINT32_MAX, find_video,
174                                     &caps, NULL);
175         }
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;
181 }
182 EXPORT_SYMBOL(acpi_video_get_capabilities);
183
184 /* Returns true if video.ko can do backlight switching */
185 int acpi_video_backlight_support(void)
186 {
187         /*
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
190          */
191         if (!acpi_video_caps_checked)
192                 acpi_video_get_capabilities(NULL);
193
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;
199
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;
205
206         /* Then go the default way */
207         return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
208 }
209 EXPORT_SYMBOL(acpi_video_backlight_support);
210
211 /*
212  * Returns true if video.ko can do display output switching.
213  * This does not work well/at all with binary graphics drivers
214  * which disable system io ranges and do it on their own.
215  */
216 int acpi_video_display_switch_support(void)
217 {
218         if (!acpi_video_caps_checked)
219                 acpi_video_get_capabilities(NULL);
220
221         if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR)
222                 return 0;
223         else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO)
224                 return 1;
225
226         if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR)
227                 return 0;
228         else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO)
229                 return 1;
230
231         return acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING;
232 }
233 EXPORT_SYMBOL(acpi_video_display_switch_support);
234
235 /*
236  * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video
237  * To force that backlight or display output switching is processed by vendor
238  * specific acpi drivers or video.ko driver.
239  */
240 static int __init acpi_backlight(char *str)
241 {
242         if (str == NULL || *str == '\0')
243                 return 1;
244         else {
245                 if (!strcmp("vendor", str))
246                         acpi_video_support |=
247                                 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
248                 if (!strcmp("video", str))
249                         acpi_video_support |=
250                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
251         }
252         return 1;
253 }
254 __setup("acpi_backlight=", acpi_backlight);
255
256 static int __init acpi_display_output(char *str)
257 {
258         if (str == NULL || *str == '\0')
259                 return 1;
260         else {
261                 if (!strcmp("vendor", str))
262                         acpi_video_support |=
263                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR;
264                 if (!strcmp("video", str))
265                         acpi_video_support |=
266                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
267         }
268         return 1;
269 }
270 __setup("acpi_display_output=", acpi_display_output);