On Thursday, March 10, 2022 6:50 PM, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
>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.
>
Yes, you are right! HF-SCDB contain the same SCDS data packet as VSDB. I will fix it later.
Best regards,
Shawn
>> +}
>> +
>> 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
>
