On Tue, 22 Feb 2022, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> 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.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 | 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.
Neither approach takes multiple CEA blocks within DisplayID extension
into account. Or some blocks outside and some inside DisplayID
extension.
I think we're going to need abstracted EDID iteration similar to what
I've done for DisplayID iteration. We can't have all places
reimplementing the iteration like we have now.
BR,
Jani.
>
> There are also several other callers of drm_find_cea_extension().
> Why don't they require the same treatment?
>
>> + 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
--
Jani Nikula, Intel Open Source Graphics Center
