Re: [v2 2/4] drm/edid: parse multiple CEA extension block

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

On Tue, Mar 01, 2022 at 04:12:14PM +0800, Lee Shawn C wrote:
> Try to find and parse more CEA ext blocks if edid->extensions
> is greater than one.
> 
> v2: split prvious patch to two. And do CEA block parsing
>     in this one.
> 
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
> Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> Signed-off-by: Lee Shawn C <shawn.c.lee@intel.com>
> ---
>  drivers/gpu/drm/drm_edid.c | 70 +++++++++++++++++++++-----------------
>  1 file changed, 38 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 375e70d9de86..e2cfde02f837 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -4319,47 +4319,53 @@ static void drm_parse_y420cmdb_bitmap(struct drm_connector *connector,
>  static int
>  add_cea_modes(struct drm_connector *connector, struct edid *edid)
>  {
> -	const u8 *cea, *db, *hdmi = NULL, *video = NULL;
> -	u8 dbl, hdmi_len, video_len = 0;
> +	const u8 *cea;
>  	int modes = 0, ext_index = 0;
>  
> -	cea = drm_find_cea_extension(edid, &ext_index);
> -	if (cea && cea_revision(cea) >= 3) {
> -		int i, start, end;
> +	for (;;) {
> +		cea = drm_find_cea_extension(edid, &ext_index);
> +		if (!cea)
> +			break;
>  
> -		if (cea_db_offsets(cea, &start, &end))
> -			return 0;
> +		if (cea && cea_revision(cea) >= 3) {
> +			const u8 *db, *hdmi = NULL, *video = NULL;
> +			u8 dbl, hdmi_len, video_len = 0;
> +			int i, start, end;

This amount of indentation is pretty horrible. Pls reverse
this if-clause to get rid of one level. Should also make
the diff much nicer.

>  
> -		for_each_cea_db(cea, i, start, end) {
> -			db = &cea[i];
> -			dbl = cea_db_payload_len(db);
> +			if (cea_db_offsets(cea, &start, &end))
> +				continue;
>  
> -			if (cea_db_tag(db) == VIDEO_BLOCK) {
> -				video = db + 1;
> -				video_len = dbl;
> -				modes += do_cea_modes(connector, video, dbl);
> -			} else if (cea_db_is_hdmi_vsdb(db)) {
> -				hdmi = db;
> -				hdmi_len = dbl;
> -			} else if (cea_db_is_y420vdb(db)) {
> -				const u8 *vdb420 = &db[2];
> -
> -				/* Add 4:2:0(only) modes present in EDID */
> -				modes += do_y420vdb_modes(connector,
> -							  vdb420,
> -							  dbl - 1);
> +			for_each_cea_db(cea, i, start, end) {
> +				db = &cea[i];
> +				dbl = cea_db_payload_len(db);
> +
> +				if (cea_db_tag(db) == VIDEO_BLOCK) {
> +					video = db + 1;
> +					video_len = dbl;
> +					modes += do_cea_modes(connector, video, dbl);
> +				} else if (cea_db_is_hdmi_vsdb(db)) {
> +					hdmi = db;
> +					hdmi_len = dbl;
> +				} else if (cea_db_is_y420vdb(db)) {
> +					const u8 *vdb420 = &db[2];
> +
> +					/* Add 4:2:0(only) modes present in EDID */
> +					modes += do_y420vdb_modes(connector,
> +								  vdb420,
> +								  dbl - 1);
> +				}
>  			}
> +
> +			/*
> +			 * We parse the HDMI VSDB after having added the cea modes as we will
> +			 * be patching their flags when the sink supports stereo 3D.
> +			 */
> +			if (hdmi)
> +				modes += do_hdmi_vsdb_modes(connector, hdmi, hdmi_len, video,
> +							    video_len);
>  		}
>  	}
>  
> -	/*
> -	 * We parse the HDMI VSDB after having added the cea modes as we will
> -	 * be patching their flags when the sink supports stereo 3D.
> -	 */
> -	if (hdmi)
> -		modes += do_hdmi_vsdb_modes(connector, hdmi, hdmi_len, video,
> -					    video_len);
> -
>  	return modes;
>  }
>  
> -- 
> 2.31.1

-- 
Ville Syrjälä
Intel