From: Sandor Yu <[email protected]>

HDMI1.4b specification section 6.5.3:
Source shall only send GCPs with non-zero CD to sinks
that indicate support for Deep Color.

DW HDMI GPC default enabled, clear gpc_auto bit for bpp 24.

Signed-off-by: Sandor Yu <[email protected]>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c 
b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index b11577de4836..c7b11582529e 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -1160,6 +1160,14 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi)
                HDMI_VP_PR_CD_DESIRED_PR_FACTOR_MASK);
        hdmi_writeb(hdmi, val, HDMI_VP_PR_CD);
 
+       val = hdmi_readb(hdmi, HDMI_FC_DATAUTO3);
+       if (color_depth == 4)
+               /* disable Auto GCP when bpp 24 */
+               val &= ~0x4;
+       else
+               val |= 0x4;
+       hdmi_writeb(hdmi, val, HDMI_FC_DATAUTO3);
+
        hdmi_modb(hdmi, HDMI_VP_STUFF_PR_STUFFING_STUFFING_MODE,
                  HDMI_VP_STUFF_PR_STUFFING_MASK, HDMI_VP_STUFF);
 
-- 
2.25.1

Reply via email to