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_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 (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 #include <linux/pci.h>
  40
  41 ACPI_MODULE_NAME("video");
  42 #define _COMPONENT              ACPI_VIDEO_COMPONENT
  43
  44 static long acpi_video_support;
  45 static bool acpi_video_caps_checked;
  46
  47 static acpi_status
  48 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
  49                           void **retyurn_value)
  50 {
  51         long *cap = context;
  52         acpi_handle h_dummy;
  53
  54         if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) &&
  55             ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) {
  56                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
  57                                   "support\n"));
  58                 *cap |= ACPI_VIDEO_BACKLIGHT;
  59                 if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy)))
  60                         printk(KERN_WARNING FW_BUG PREFIX "ACPI brightness "
  61                                         "control misses _BQC function\n");
  62                 /* We have backlight support, no need to scan further */
  63                 return AE_CTRL_TERMINATE;
  64         }
  65         return 0;
  66 }
  67
  68 /* Returns true if the device is a video device which can be handled by
  69  * video.ko.
  70  * The device will get a Linux specific CID added in scan.c to
  71  * identify the device as an ACPI graphics device
  72  * Be aware that the graphics device may not be physically present
  73  * Use acpi_video_get_capabilities() to detect general ACPI video
  74  * capabilities of present cards
  75  */
  76 long acpi_is_video_device(struct acpi_device *device)
  77 {
  78         acpi_handle h_dummy;
  79         long video_caps = 0;
  80
  81         if (!device)
  82                 return 0;
  83
  84         /* Does this device able to support video switching ? */
  85         if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) &&
  86             ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy)))
  87                 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
  88
  89         /* Does this device able to retrieve a video ROM ? */
  90         if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy)))
  91                 video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
  92
  93         /* Does this device able to configure which video head to be POSTed ? */
  94         if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) &&
  95             ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) &&
  96             ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy)))
  97                 video_caps |= ACPI_VIDEO_DEVICE_POSTING;
  98
  99         /* Only check for backlight functionality if one of the above hit. */
 100         if (video_caps)
 101                 acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle,
 102                                     ACPI_UINT32_MAX, acpi_backlight_cap_match,
 103                                     &video_caps, NULL);
 104
 105         return video_caps;
 106 }
 107 EXPORT_SYMBOL(acpi_is_video_device);
 108
 109 static acpi_status
 110 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
 111 {
 112         long *cap = context;
 113         struct pci_dev *dev;
 114         struct acpi_device *acpi_dev;
 115
 116         const struct acpi_device_id video_ids[] = {
 117                 {ACPI_VIDEO_HID, 0},
 118                 {"", 0},
 119         };
 120         if (acpi_bus_get_device(handle, &acpi_dev))
 121                 return AE_OK;
 122
 123         if (!acpi_match_device_ids(acpi_dev, video_ids)) {
 124                 dev = acpi_get_pci_dev(handle);
 125                 if (!dev)
 126                         return AE_OK;
 127                 pci_dev_put(dev);
 128                 *cap |= acpi_is_video_device(acpi_dev);
 129         }
 130         return AE_OK;
 131 }
 132
 133 /*
 134  * Returns the video capabilities of a specific ACPI graphics device
 135  *
 136  * if NULL is passed as argument all ACPI devices are enumerated and
 137  * all graphics capabilities of physically present devices are
 138  * summerized and returned. This is cached and done only once.
 139  */
 140 long acpi_video_get_capabilities(acpi_handle graphics_handle)
 141 {
 142         long caps = 0;
 143         struct acpi_device *tmp_dev;
 144         acpi_status status;
 145
 146         if (acpi_video_caps_checked && graphics_handle == NULL)
 147                 return acpi_video_support;
 148
 149         if (!graphics_handle) {
 150                 /* Only do the global walk through all graphics devices once */
 151                 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 152                                     ACPI_UINT32_MAX, find_video,
 153                                     &caps, NULL);
 154                 /* There might be boot param flags set already... */
 155                 acpi_video_support |= caps;
 156                 acpi_video_caps_checked = 1;
 157                 /* Add blacklists here. Be careful to use the right *DMI* bits
 158                  * to still be able to override logic via boot params, e.g.:
 159                  *
 160                  *   if (dmi_name_in_vendors("XY")) {
 161                  *      acpi_video_support |=
 162                  *              ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR;
 163                  *      acpi_video_support |=
 164                  *              ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 165                  *}
 166                  */
 167         } else {
 168                 status = acpi_bus_get_device(graphics_handle, &tmp_dev);
 169                 if (ACPI_FAILURE(status)) {
 170                         ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
 171                         return 0;
 172                 }
 173                 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
 174                                     ACPI_UINT32_MAX, find_video,
 175                                     &caps, NULL);
 176         }
 177         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
 178                           graphics_handle ? caps : acpi_video_support,
 179                           graphics_handle ? "on device " : "in general",
 180                           graphics_handle ? acpi_device_bid(tmp_dev) : ""));
 181         return caps;
 182 }
 183 EXPORT_SYMBOL(acpi_video_get_capabilities);
 184
 185 /* Returns true if video.ko can do backlight switching */
 186 int acpi_video_backlight_support(void)
 187 {
 188         /*
 189          * We must check whether the ACPI graphics device is physically plugged
 190          * in. Therefore this must be called after binding PCI and ACPI devices
 191          */
 192         if (!acpi_video_caps_checked)
 193                 acpi_video_get_capabilities(NULL);
 194
 195         /* First check for boot param -> highest prio */
 196         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
 197                 return 0;
 198         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
 199                 return 1;
 200
 201         /* Then check for DMI blacklist -> second highest prio */
 202         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
 203                 return 0;
 204         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
 205                 return 1;
 206
 207         /* Then go the default way */
 208         return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
 209 }
 210 EXPORT_SYMBOL(acpi_video_backlight_support);
 211
 212 /*
 213  * Returns true if video.ko can do display output switching.
 214  * This does not work well/at all with binary graphics drivers
 215  * which disable system io ranges and do it on their own.
 216  */
 217 int acpi_video_display_switch_support(void)
 218 {
 219         if (!acpi_video_caps_checked)
 220                 acpi_video_get_capabilities(NULL);
 221
 222         if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR)
 223                 return 0;
 224         else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO)
 225                 return 1;
 226
 227         if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR)
 228                 return 0;
 229         else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO)
 230                 return 1;
 231
 232         return acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING;
 233 }
 234 EXPORT_SYMBOL(acpi_video_display_switch_support);
 235
 236 /*
 237  * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video
 238  * To force that backlight or display output switching is processed by vendor
 239  * specific acpi drivers or video.ko driver.
 240  */
 241 static int __init acpi_backlight(char *str)
 242 {
 243         if (str == NULL || *str == '\0')
 244                 return 1;
 245         else {
 246                 if (!strcmp("vendor", str))
 247                         acpi_video_support |=
 248                                 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
 249                 if (!strcmp("video", str))
 250                         acpi_video_support |=
 251                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
 252         }
 253         return 1;
 254 }
 255 __setup("acpi_backlight=", acpi_backlight);
 256
 257 static int __init acpi_display_output(char *str)
 258 {
 259         if (str == NULL || *str == '\0')
 260                 return 1;
 261         else {
 262                 if (!strcmp("vendor", str))
 263                         acpi_video_support |=
 264                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR;
 265                 if (!strcmp("video", str))
 266                         acpi_video_support |=
 267                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
 268         }
 269         return 1;
 270 }
 271 __setup("acpi_display_output=", acpi_display_output);