On Wed, Mar 02, 2022 at 05:35:11PM +0800, Lee Shawn C wrote: > Find HF-SCDB information in CEA extensions block. And retrieve > Max_TMDS_Character_Rate that support by sink device. > > Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> > Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx> > Cc: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx> > Signed-off-by: Lee Shawn C <shawn.c.lee@xxxxxxxxx> > --- > drivers/gpu/drm/drm_edid.c | 36 ++++++++++++++++++++++++++++++++++++ > 1 file changed, 36 insertions(+) > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 2b8ddc956ce2..d6b48c543c23 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -3350,6 +3350,7 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid, > #define EXT_VIDEO_DATA_BLOCK_420 0x0E > #define EXT_VIDEO_CAP_BLOCK_Y420CMDB 0x0F > #define EXT_VIDEO_HF_EEODB_DATA_BLOCK 0x78 > +#define EXT_VIDEO_HF_SCDB_DATA_BLOCK 0x79 > #define EDID_BASIC_AUDIO (1 << 6) > #define EDID_CEA_YCRCB444 (1 << 5) > #define EDID_CEA_YCRCB422 (1 << 4) > @@ -4277,6 +4278,20 @@ static bool cea_db_is_vcdb(const u8 *db) > return true; > } > > +static bool cea_db_is_hf_scdb(const u8 *db) > +{ > + if (cea_db_tag(db) != USE_EXTENDED_TAG) > + return false; > + > + if (cea_db_payload_len(db) < 7) > + return false; > + > + if (cea_db_extended_tag(db) != EXT_VIDEO_HF_SCDB_DATA_BLOCK) > + return false; > + > + return true; > +} > + > static bool cea_db_is_y420cmdb(const u8 *db) > { > if (cea_db_tag(db) != USE_EXTENDED_TAG) > @@ -4987,6 +5002,25 @@ static void drm_parse_vcdb(struct drm_connector *connector, const u8 *db) > info->rgb_quant_range_selectable = true; > } > > +static void drm_parse_hf_scdb(struct drm_connector *connector, const u8 *db) > +{ > + struct drm_display_info *info = &connector->display_info; > + u32 max_tmds_clock; > + > + DRM_DEBUG_KMS("HF-SCDB version 0x%02x\n", db[4]); > + > + max_tmds_clock = db[5] * 5000; > + if (info->max_tmds_clock < max_tmds_clock) { > + info->max_tmds_clock = max_tmds_clock; > + DRM_DEBUG_KMS("HF-SCDB: max TMDS clock %d kHz\n", > + info->max_tmds_clock); > + } > + > + /* > + * ToDo: Parse the remaining SCDB data if needed > + */ If I'm reading the spec right this block should contain the exact same stuff as the HF-VSDB. We should reuse the same code for parsing both. > +} > + > static > void drm_get_max_frl_rate(int max_frl_rate, u8 *max_lanes, u8 *max_rate_per_lane) > { > @@ -5282,6 +5316,8 @@ static void drm_parse_cea_ext(struct drm_connector *connector, > drm_parse_y420cmdb_bitmap(connector, db); > if (cea_db_is_vcdb(db)) > drm_parse_vcdb(connector, db); > + if (cea_db_is_hf_scdb(db)) > + drm_parse_hf_scdb(connector, db); > if (cea_db_is_hdmi_hdr_metadata_block(db)) > drm_parse_hdr_metadata_block(connector, db); > } > -- > 2.17.1 -- Ville Syrjälä Intel