On Tue, Feb 22, 2022 at 03:28:17PM +0800, Ville Syrjälä 
<ville.syrj...@linux.intel.com> wrote:
>On Tue, Feb 22, 2022 at 02:38:17PM +0800, Lee Shawn C wrote:
>> Try to find and parse more CEA ext blocks if edid->extensions is 
>> greater than one.
>> 
>> Cc: Jani Nikula <jani.nik...@linux.intel.com>
>> Cc: Ville Syrjala <ville.syrj...@linux.intel.com>
>> Cc: Ankit Nautiyal <ankit.k.nauti...@intel.com>
>> Signed-off-by: Lee Shawn C <shawn.c....@intel.com>
>> ---
>>  drivers/gpu/drm/drm_edid.c | 75 
>> +++++++++++++++++++++++---------------
>>  1 file changed, 45 insertions(+), 30 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c 
>> index 12893e7be89b..3d5dbbeca7f9 100644
>> --- a/drivers/gpu/drm/drm_edid.c
>> +++ b/drivers/gpu/drm/drm_edid.c
>> @@ -4313,43 +4313,58 @@ add_cea_modes(struct drm_connector *connector, 
>> struct edid *edid)
>>      const u8 *cea = drm_find_cea_extension(edid);
>>      const u8 *db, *hdmi = NULL, *video = NULL;
>>      u8 dbl, hdmi_len, video_len = 0;
>> -    int modes = 0;
>> +    int modes = 0, j;
>>  
>> -    if (cea && cea_revision(cea) >= 3) {
>> -            int i, start, end;
>> +    if (!cea)
>> +            return 0;
>>  
>> -            if (cea_db_offsets(cea, &start, &end))
>> -                    return 0;
>> +    for (j = (cea - (u8 *)edid) / EDID_LENGTH; j <= edid->extensions;) {
>
>That looks rather illegible. I think we want a drm_find_cea_extension(const 
>struct edid *edid, int *ext_index) and then just loop until it stops giving us 
>stuff.
>

I will modify drm_find_cea_extension() to find out next CEA from *ext_index.

>There are also several other callers of drm_find_cea_extension().
>Why don't they require the same treatment?

My suspicion is the original design judge edid->extension would be zero or one. 
And only one extension block would available.

Best regards,
Shawn

>
>> +            if (cea && cea_revision(cea) >= 3) {
>> +                    int i, start, end;
>>  
>> -            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);
>> +                    hdmi  = NULL;
>> +                    video = NULL;
>> +                    hdmi_len = 0;
>> +                    video_len = 0;
>> +            }
>> +
>> +            /* move to next CEA extension block */
>> +            cea = drm_find_edid_extension(edid, CEA_EXT, &j);
>> +            if (!cea)
>> +                    break;
>> +    }
>>  
>>      return modes;
>>  }
>> --
>> 2.17.1
>
>--
>Ville Syrjälä
>Intel
>

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