[v8 2/5] drm/edid: parse multiple CEA extension block

[Lee Shawn C <shawn.c.lee@xxxxxxxxx>]

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.
v3: simplify this patch based on previous change.
v4: refine patch v3.
v5: revert previous change.
    And check cea pointer return from drm_find_cea_extension().
    If drvier got the same cea pointer then exit this routine.

Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
Cc: Drew Davenport <ddavenport@xxxxxxxxxxxx>
Cc: intel-gfx <intel-gfx@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Lee Shawn C <shawn.c.lee@xxxxxxxxx>
---
 drivers/gpu/drm/drm_edid.c | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 1251226d9284..ef65dd97d700 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -4319,16 +4319,24 @@ 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;
 	int modes = 0, ext_index = 0;
+	const u8 *cur_cea = NULL;
 
-	cea = drm_find_cea_extension(edid, &ext_index);
-	if (cea && cea_revision(cea) >= 3) {
+	for (;;) {
+		const u8 *cea, *db, *hdmi = NULL, *video = NULL;
+		u8 dbl, hdmi_len = 0, video_len = 0;
 		int i, start, end;
 
+		cea = drm_find_cea_extension(edid, &ext_index);
+		if (!cea || cea == cur_cea)
+			break;
+		cur_cea = cea;
+
+		if (cea_revision(cea) < 3)
+			continue;
+
 		if (cea_db_offsets(cea, &start, &end))
-			return 0;
+			continue;
 
 		for_each_cea_db(cea, i, start, end) {
 			db = &cea[i];
@@ -4350,15 +4358,15 @@ add_cea_modes(struct drm_connector *connector, struct edid *edid)
 							  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;
 }
-- 
2.17.1