LXR linux/drivers/acpi/video

   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
  40ACPI_MODULE_NAME("video");
  41#define _COMPONENT              ACPI_VIDEO_COMPONENT
  42
  43static long acpi_video_support;
  44static bool acpi_video_caps_checked;
  45
  46static acpi_status
  47acpi_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 */
  75long 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}
 106EXPORT_SYMBOL(acpi_is_video_device);
 107
 108static acpi_status
 109find_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 */
 139long 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}
 182EXPORT_SYMBOL(acpi_video_get_capabilities);
 183
 184/* Returns true if video.ko can do backlight switching */
 185int 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}
 209EXPORT_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 */
 216int 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}
 233EXPORT_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 */
 240static 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
 256static 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);
 271