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drm/edid: support Microsoft extension for HMDs and specialized monitors

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Add minimal support for parsing VSDBs documented in Microsoft's "EDID
extension for head-mounted and specialized monitors" [1]. The version
field and the desktop usage flag can be used to set the non_desktop
connector property.

[1] https://docs.microsoft.com/en-us/windows-hardware/drivers/display/specialized-monitors-edid-extension

Tested with HPN-36C1 and LEN-B800.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220123101653.147333-1-philipp.zabel@gmail.com
This commit is contained in:
Philipp Zabel 2022-01-23 11:16:52 +01:00 committed by Jani Nikula
parent b3bddb7a38
commit 2869f599c0
1 changed files with 34 additions and 0 deletions
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34
drivers/gpu/drm/drm_edid.c
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@ -93,6 +93,8 @@ static int oui(u8 first, u8 second, u8 third)
/* Non desktop display (i.e. HMD) */
#define EDID_QUIRK_NON_DESKTOP (1 << 12)
#define MICROSOFT_IEEE_OUI 0xca125c
struct detailed_mode_closure {
struct drm_connector *connector;
struct edid *edid;
@ -4222,6 +4224,17 @@ static bool cea_db_is_hdmi_forum_vsdb(const u8 *db)
return oui(db[3], db[2], db[1]) == HDMI_FORUM_IEEE_OUI;
}
static bool cea_db_is_microsoft_vsdb(const u8 *db)
{
if (cea_db_tag(db) != VENDOR_BLOCK)
return false;
if (cea_db_payload_len(db) != 21)
return false;
return oui(db[3], db[2], db[1]) == MICROSOFT_IEEE_OUI;
}
static bool cea_db_is_vcdb(const u8 *db)
{
if (cea_db_tag(db) != USE_EXTENDED_TAG)
@ -5149,6 +5162,25 @@ drm_parse_hdmi_vsdb_video(struct drm_connector *connector, const u8 *db)
drm_parse_hdmi_deep_color_info(connector, db);
}
/*
* See EDID extension for head-mounted and specialized monitors, specified at:
* https://docs.microsoft.com/en-us/windows-hardware/drivers/display/specialized-monitors-edid-extension
*/
static void drm_parse_microsoft_vsdb(struct drm_connector *connector,
const u8 *db)
{
struct drm_display_info *info = &connector->display_info;
u8 version = db[4];
bool desktop_usage = db[5] & BIT(6);
/* Version 1 and 2 for HMDs, version 3 flags desktop usage explicitly */
if (version == 1 || version == 2 || (version == 3 && !desktop_usage))
info->non_desktop = true;
drm_dbg_kms(connector->dev, "HMD or specialized display VSDB version %u: 0x%02x\n",
version, db[5]);
}
static void drm_parse_cea_ext(struct drm_connector *connector,
const struct edid *edid)
{
@ -5179,6 +5211,8 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
drm_parse_hdmi_vsdb_video(connector, db);
if (cea_db_is_hdmi_forum_vsdb(db))
drm_parse_hdmi_forum_vsdb(connector, db);
if (cea_db_is_microsoft_vsdb(db))
drm_parse_microsoft_vsdb(connector, db);
if (cea_db_is_y420cmdb(db))
drm_parse_y420cmdb_bitmap(connector, db);
if (cea_db_is_vcdb(db))