drm/edid: Add quirk for Sony PVM-2541A to get 12 bpc hdmi deep color.

The Sony PVM-2541A OLED high precision color display supports
both 10 bpc and 12 bpc hdmi deep color input, but its edid
does not signal any deep color support.

Add a quirk to force it being treated as a 12 bpc panel.
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/drm_edid.c

@@ -70,6 +70,8 @@
 #define EDID_QUIRK_FORCE_REDUCED_BLANKING	(1 << 7)
 /* Force 8bpc */
 #define EDID_QUIRK_FORCE_8BPC			(1 << 8)
+/* Force 12bpc */
+#define EDID_QUIRK_FORCE_12BPC			(1 << 9)
 
 struct detailed_mode_closure {
 	struct drm_connector *connector;
@@ -125,6 +127,9 @@ static struct edid_quirk {
 	{ "SAM", 596, EDID_QUIRK_PREFER_LARGE_60 },
 	{ "SAM", 638, EDID_QUIRK_PREFER_LARGE_60 },
 
+	/* Sony PVM-2541A does up to 12 bpc, but only reports max 8 bpc */
+	{ "SNY", 0x2541, EDID_QUIRK_FORCE_12BPC },
+
 	/* ViewSonic VA2026w */
 	{ "VSC", 5020, EDID_QUIRK_FORCE_REDUCED_BLANKING },
 
@@ -3660,6 +3665,9 @@ int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
 	if (quirks & EDID_QUIRK_FORCE_8BPC)
 		connector->display_info.bpc = 8;
 
+	if (quirks & EDID_QUIRK_FORCE_12BPC)
+		connector->display_info.bpc = 12;
+
 	return num_modes;
 }
 EXPORT_SYMBOL(drm_add_edid_modes);