linux/drivers/acpi/video_detect.c
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   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#include "internal.h"
  42
  43#define PREFIX "ACPI: "
  44
  45ACPI_MODULE_NAME("video");
  46#define _COMPONENT              ACPI_VIDEO_COMPONENT
  47
  48static long acpi_video_support;
  49static bool acpi_video_caps_checked;
  50
  51static acpi_status
  52acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
  53                          void **retyurn_value)
  54{
  55        long *cap = context;
  56
  57        if (acpi_has_method(handle, "_BCM") &&
  58            acpi_has_method(handle, "_BCL")) {
  59                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
  60                                  "support\n"));
  61                *cap |= ACPI_VIDEO_BACKLIGHT;
  62                if (!acpi_has_method(handle, "_BQC"))
  63                        printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
  64                                "cannot determine initial brightness\n");
  65                /* We have backlight support, no need to scan further */
  66                return AE_CTRL_TERMINATE;
  67        }
  68        return 0;
  69}
  70
  71/* Returns true if the ACPI object is a video device which can be
  72 * handled by video.ko.
  73 * The device will get a Linux specific CID added in scan.c to
  74 * identify the device as an ACPI graphics device
  75 * Be aware that the graphics device may not be physically present
  76 * Use acpi_video_get_capabilities() to detect general ACPI video
  77 * capabilities of present cards
  78 */
  79long acpi_is_video_device(acpi_handle handle)
  80{
  81        long video_caps = 0;
  82
  83        /* Is this device able to support video switching ? */
  84        if (acpi_has_method(handle, "_DOD") || acpi_has_method(handle, "_DOS"))
  85                video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
  86
  87        /* Is this device able to retrieve a video ROM ? */
  88        if (acpi_has_method(handle, "_ROM"))
  89                video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
  90
  91        /* Is this device able to configure which video head to be POSTed ? */
  92        if (acpi_has_method(handle, "_VPO") &&
  93            acpi_has_method(handle, "_GPD") &&
  94            acpi_has_method(handle, "_SPD"))
  95                video_caps |= ACPI_VIDEO_DEVICE_POSTING;
  96
  97        /* Only check for backlight functionality if one of the above hit. */
  98        if (video_caps)
  99                acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
 100                                    ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
 101                                    &video_caps, NULL);
 102
 103        return video_caps;
 104}
 105EXPORT_SYMBOL(acpi_is_video_device);
 106
 107static acpi_status
 108find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
 109{
 110        long *cap = context;
 111        struct pci_dev *dev;
 112        struct acpi_device *acpi_dev;
 113
 114        const struct acpi_device_id video_ids[] = {
 115                {ACPI_VIDEO_HID, 0},
 116                {"", 0},
 117        };
 118        if (acpi_bus_get_device(handle, &acpi_dev))
 119                return AE_OK;
 120
 121        if (!acpi_match_device_ids(acpi_dev, video_ids)) {
 122                dev = acpi_get_pci_dev(handle);
 123                if (!dev)
 124                        return AE_OK;
 125                pci_dev_put(dev);
 126                *cap |= acpi_is_video_device(handle);
 127        }
 128        return AE_OK;
 129}
 130
 131/* Force to use vendor driver when the ACPI device is known to be
 132 * buggy */
 133static int video_detect_force_vendor(const struct dmi_system_id *d)
 134{
 135        acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 136        return 0;
 137}
 138
 139static struct dmi_system_id video_detect_dmi_table[] = {
 140        /* On Samsung X360, the BIOS will set a flag (VDRV) if generic
 141         * ACPI backlight device is used. This flag will definitively break
 142         * the backlight interface (even the vendor interface) untill next
 143         * reboot. It's why we should prevent video.ko from being used here
 144         * and we can't rely on a later call to acpi_video_unregister().
 145         */
 146        {
 147         .callback = video_detect_force_vendor,
 148         .ident = "X360",
 149         .matches = {
 150                DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 151                DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
 152                DMI_MATCH(DMI_BOARD_NAME, "X360"),
 153                },
 154        },
 155        {
 156        .callback = video_detect_force_vendor,
 157        .ident = "Asus UL30VT",
 158        .matches = {
 159                DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 160                DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
 161                },
 162        },
 163        {
 164        .callback = video_detect_force_vendor,
 165        .ident = "Asus UL30A",
 166        .matches = {
 167                DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 168                DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"),
 169                },
 170        },
 171        { },
 172};
 173
 174/*
 175 * Returns the video capabilities of a specific ACPI graphics device
 176 *
 177 * if NULL is passed as argument all ACPI devices are enumerated and
 178 * all graphics capabilities of physically present devices are
 179 * summarized and returned. This is cached and done only once.
 180 */
 181long acpi_video_get_capabilities(acpi_handle graphics_handle)
 182{
 183        long caps = 0;
 184        struct acpi_device *tmp_dev;
 185        acpi_status status;
 186
 187        if (acpi_video_caps_checked && graphics_handle == NULL)
 188                return acpi_video_support;
 189
 190        if (!graphics_handle) {
 191                /* Only do the global walk through all graphics devices once */
 192                acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 193                                    ACPI_UINT32_MAX, find_video, NULL,
 194                                    &caps, NULL);
 195                /* There might be boot param flags set already... */
 196                acpi_video_support |= caps;
 197                acpi_video_caps_checked = 1;
 198                /* Add blacklists here. Be careful to use the right *DMI* bits
 199                 * to still be able to override logic via boot params, e.g.:
 200                 *
 201                 *   if (dmi_name_in_vendors("XY")) {
 202                 *      acpi_video_support |=
 203                 *              ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 204                 *}
 205                 */
 206
 207                dmi_check_system(video_detect_dmi_table);
 208        } else {
 209                status = acpi_bus_get_device(graphics_handle, &tmp_dev);
 210                if (ACPI_FAILURE(status)) {
 211                        ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
 212                        return 0;
 213                }
 214                acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
 215                                    ACPI_UINT32_MAX, find_video, NULL,
 216                                    &caps, NULL);
 217        }
 218        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
 219                          graphics_handle ? caps : acpi_video_support,
 220                          graphics_handle ? "on device " : "in general",
 221                          graphics_handle ? acpi_device_bid(tmp_dev) : ""));
 222        return caps;
 223}
 224EXPORT_SYMBOL(acpi_video_get_capabilities);
 225
 226static void acpi_video_caps_check(void)
 227{
 228        /*
 229         * We must check whether the ACPI graphics device is physically plugged
 230         * in. Therefore this must be called after binding PCI and ACPI devices
 231         */
 232        if (!acpi_video_caps_checked)
 233                acpi_video_get_capabilities(NULL);
 234}
 235
 236bool acpi_video_backlight_quirks(void)
 237{
 238        return acpi_gbl_osi_data >= ACPI_OSI_WIN_8;
 239}
 240EXPORT_SYMBOL(acpi_video_backlight_quirks);
 241
 242/* Promote the vendor interface instead of the generic video module.
 243 * This function allow DMI blacklists to be implemented by externals
 244 * platform drivers instead of putting a big blacklist in video_detect.c
 245 * After calling this function you will probably want to call
 246 * acpi_video_unregister() to make sure the video module is not loaded
 247 */
 248void acpi_video_dmi_promote_vendor(void)
 249{
 250        acpi_video_caps_check();
 251        acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 252}
 253EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
 254
 255/* To be called when a driver who previously promoted the vendor
 256 * interface */
 257void acpi_video_dmi_demote_vendor(void)
 258{
 259        acpi_video_caps_check();
 260        acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 261}
 262EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
 263
 264/* Returns true if video.ko can do backlight switching */
 265int acpi_video_backlight_support(void)
 266{
 267        acpi_video_caps_check();
 268
 269        /* First check for boot param -> highest prio */
 270        if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
 271                return 0;
 272        else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
 273                return 1;
 274
 275        /* Then check for DMI blacklist -> second highest prio */
 276        if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
 277                return 0;
 278        else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
 279                return 1;
 280
 281        /* Then go the default way */
 282        return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
 283}
 284EXPORT_SYMBOL(acpi_video_backlight_support);
 285
 286/*
 287 * Use acpi_backlight=vendor/video to force that backlight switching
 288 * is processed by vendor specific acpi drivers or video.ko driver.
 289 */
 290static int __init acpi_backlight(char *str)
 291{
 292        if (str == NULL || *str == '\0')
 293                return 1;
 294        else {
 295                if (!strcmp("vendor", str))
 296                        acpi_video_support |=
 297                                ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
 298                if (!strcmp("video", str))
 299                        acpi_video_support |=
 300                                ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
 301        }
 302        return 1;
 303}
 304__setup("acpi_backlight=", acpi_backlight);
 305
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