Re: [PATCH 02/19] drm/edid: check for HF-SCDB block

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Apr 14, 2022 at 06:06:45PM +0300, Jani Nikula wrote:
> From: Lee Shawn C <shawn.c.lee@intel.com>
> 
> Find HF-SCDB information in CEA extensions block. And retrieve
> Max_TMDS_Character_Rate that support by sink device.
> 
> v2: HF-SCDB and HF-VSDBS carry the same SCDS data. Reuse
>     drm_parse_hdmi_forum_vsdb() to parse this packet.
> 
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
> Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> Cc: intel-gfx <intel-gfx@lists.freedesktop.org>
> Signed-off-by: Lee Shawn C <shawn.c.lee@intel.com>
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/drm_edid.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 4758e78fad82..32ece9607b94 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -3495,6 +3495,7 @@ add_detailed_modes(struct drm_connector *connector, const struct edid *edid,
>  #define EXT_VIDEO_CAPABILITY_BLOCK 0x00
>  #define EXT_VIDEO_DATA_BLOCK_420	0x0E
>  #define EXT_VIDEO_CAP_BLOCK_Y420CMDB 0x0F
> +#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)
> @@ -4426,6 +4427,20 @@ static bool cea_db_is_vcdb(const u8 *db)
>  	return true;
>  }
>  
> +static bool cea_db_is_hdmi_forum_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)
> @@ -5387,7 +5402,8 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
>  
>  		if (cea_db_is_hdmi_vsdb(db))
>  			drm_parse_hdmi_vsdb_video(connector, db);
> -		if (cea_db_is_hdmi_forum_vsdb(db))
> +		if (cea_db_is_hdmi_forum_vsdb(db) ||
> +		    cea_db_is_hdmi_forum_scdb(db))
>  			drm_parse_hdmi_forum_vsdb(connector, db);

I'd do a s/parse_hdmi_forum_vsdb/parse_scds/ to keep up
with the spec terminology.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

>  		if (cea_db_is_microsoft_vsdb(db))
>  			drm_parse_microsoft_vsdb(connector, db);
> -- 
> 2.30.2

-- 
Ville Syrjälä
Intel