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  * assigned
  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 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-laptop,
  27  * sony_acpi,... can take care about backlight brightness.
  28  *
  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.
  33  *
  34  */
  35
  36 #include <linux/export.h>
  37 #include <linux/acpi.h>
  38 #include <linux/dmi.h>
  39 #include <linux/pci.h>
  40
  41 #define PREFIX "ACPI: "
  42
  43 ACPI_MODULE_NAME("video");
  44 #define _COMPONENT              ACPI_VIDEO_COMPONENT
  45
  46 static long acpi_video_support;
  47 static bool acpi_video_caps_checked;
  48
  49 static acpi_status
  50 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
  51                           void **retyurn_value)
  52 {
  53         long *cap = context;
  54         acpi_handle h_dummy;
  55
  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 "
  59                                   "support\n"));
  60                 *cap |= ACPI_VIDEO_BACKLIGHT;
  61                 if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy)))
  62                         printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
  63                                 "cannot determine initial brightness\n");
  64                 /* We have backlight support, no need to scan further */
  65                 return AE_CTRL_TERMINATE;
  66         }
  67         return 0;
  68 }
  69
  70 /* Returns true if the ACPI object is a video device which can be
  71  * handled by video.ko.
  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
  77  */
  78 long acpi_is_video_device(acpi_handle handle)
  79 {
  80         acpi_handle h_dummy;
  81         long video_caps = 0;
  82
  83         /* Is this device able to support video switching ? */
  84         if (ACPI_SUCCESS(acpi_get_handle(handle, "_DOD", &h_dummy)) ||
  85             ACPI_SUCCESS(acpi_get_handle(handle, "_DOS", &h_dummy)))
  86                 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
  87
  88         /* Is this device able to retrieve a video ROM ? */
  89         if (ACPI_SUCCESS(acpi_get_handle(handle, "_ROM", &h_dummy)))
  90                 video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
  91
  92         /* Is this device able to configure which video head to be POSTed ? */
  93         if (ACPI_SUCCESS(acpi_get_handle(handle, "_VPO", &h_dummy)) &&
  94             ACPI_SUCCESS(acpi_get_handle(handle, "_GPD", &h_dummy)) &&
  95             ACPI_SUCCESS(acpi_get_handle(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, handle,
 101                                     ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
 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 pci_dev *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_pci_dev(handle);
 124                 if (!dev)
 125                         return AE_OK;
 126                 pci_dev_put(dev);
 127                 *cap |= acpi_is_video_device(handle);
 128         }
 129         return AE_OK;
 130 }
 131
 132 /* Force to use vendor driver when the ACPI device is known to be
 133  * buggy */
 134 static int video_detect_force_vendor(const struct dmi_system_id *d)
 135 {
 136         acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 137         return 0;
 138 }
 139
 140 static struct dmi_system_id video_detect_dmi_table[] = {
 141         /* On Samsung X360, the BIOS will set a flag (VDRV) if generic
 142          * ACPI backlight device is used. This flag will definitively break
 143          * the backlight interface (even the vendor interface) untill next
 144          * reboot. It's why we should prevent video.ko from being used here
 145          * and we can't rely on a later call to acpi_video_unregister().
 146          */
 147         {
 148          .callback = video_detect_force_vendor,
 149          .ident = "X360",
 150          .matches = {
 151                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 152                 DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
 153                 DMI_MATCH(DMI_BOARD_NAME, "X360"),
 154                 },
 155         },
 156         {
 157         .callback = video_detect_force_vendor,
 158         .ident = "Asus UL30VT",
 159         .matches = {
 160                 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 161                 DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
 162                 },
 163         },
 164         { },
 165 };
 166
 167 /*
 168  * Returns the video capabilities of a specific ACPI graphics device
 169  *
 170  * if NULL is passed as argument all ACPI devices are enumerated and
 171  * all graphics capabilities of physically present devices are
 172  * summarized and returned. This is cached and done only once.
 173  */
 174 long acpi_video_get_capabilities(acpi_handle graphics_handle)
 175 {
 176         long caps = 0;
 177         struct acpi_device *tmp_dev;
 178         acpi_status status;
 179
 180         if (acpi_video_caps_checked && graphics_handle == NULL)
 181                 return acpi_video_support;
 182
 183         if (!graphics_handle) {
 184                 /* Only do the global walk through all graphics devices once */
 185                 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 186                                     ACPI_UINT32_MAX, find_video, NULL,
 187                                     &caps, NULL);
 188                 /* There might be boot param flags set already... */
 189                 acpi_video_support |= caps;
 190                 acpi_video_caps_checked = 1;
 191                 /* Add blacklists here. Be careful to use the right *DMI* bits
 192                  * to still be able to override logic via boot params, e.g.:
 193                  *
 194                  *   if (dmi_name_in_vendors("XY")) {
 195                  *      acpi_video_support |=
 196                  *              ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 197                  *}
 198                  */
 199
 200                 dmi_check_system(video_detect_dmi_table);
 201         } else {
 202                 status = acpi_bus_get_device(graphics_handle, &tmp_dev);
 203                 if (ACPI_FAILURE(status)) {
 204                         ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
 205                         return 0;
 206                 }
 207                 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
 208                                     ACPI_UINT32_MAX, find_video, NULL,
 209                                     &caps, NULL);
 210         }
 211         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
 212                           graphics_handle ? caps : acpi_video_support,
 213                           graphics_handle ? "on device " : "in general",
 214                           graphics_handle ? acpi_device_bid(tmp_dev) : ""));
 215         return caps;
 216 }
 217 EXPORT_SYMBOL(acpi_video_get_capabilities);
 218
 219 static void acpi_video_caps_check(void)
 220 {
 221         /*
 222          * We must check whether the ACPI graphics device is physically plugged
 223          * in. Therefore this must be called after binding PCI and ACPI devices
 224          */
 225         if (!acpi_video_caps_checked)
 226                 acpi_video_get_capabilities(NULL);
 227 }
 228
 229 /* Promote the vendor interface instead of the generic video module.
 230  * This function allow DMI blacklists to be implemented by externals
 231  * platform drivers instead of putting a big blacklist in video_detect.c
 232  * After calling this function you will probably want to call
 233  * acpi_video_unregister() to make sure the video module is not loaded
 234  */
 235 void acpi_video_dmi_promote_vendor(void)
 236 {
 237         acpi_video_caps_check();
 238         acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 239 }
 240 EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
 241
 242 /* To be called when a driver who previously promoted the vendor
 243  * interface */
 244 void acpi_video_dmi_demote_vendor(void)
 245 {
 246         acpi_video_caps_check();
 247         acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 248 }
 249 EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
 250
 251 /* Returns true if video.ko can do backlight switching */
 252 int acpi_video_backlight_support(void)
 253 {
 254         acpi_video_caps_check();
 255
 256         /* First check for boot param -> highest prio */
 257         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
 258                 return 0;
 259         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
 260                 return 1;
 261
 262         /* Then check for DMI blacklist -> second highest prio */
 263         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
 264                 return 0;
 265         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
 266                 return 1;
 267
 268         /* Then go the default way */
 269         return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
 270 }
 271 EXPORT_SYMBOL(acpi_video_backlight_support);
 272
 273 /*
 274  * Use acpi_backlight=vendor/video to force that backlight switching
 275  * is processed by vendor specific acpi drivers or video.ko driver.
 276  */
 277 static int __init acpi_backlight(char *str)
 278 {
 279         if (str == NULL || *str == '\0')
 280                 return 1;
 281         else {
 282                 if (!strcmp("vendor", str))
 283                         acpi_video_support |=
 284                                 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
 285                 if (!strcmp("video", str))
 286                         acpi_video_support |=
 287                                 ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
 288         }
 289         return 1;
 290 }
 291 __setup("acpi_backlight=", acpi_backlight);