Messages in this thread | | | Date | Fri, 8 Apr 2022 14:40:23 +0200 | Subject | Re: [PATCH v2 3/5] drm: bridge: dw_hdmi: Enable GCP only for Deep Color | From | Neil Armstrong <> |
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On 08/04/2022 12:32, Sandor Yu wrote: > 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 GCP default enabled, clear gpc_auto bit for 24-bit color depth.
It's right because we do not handle AVMUTE, Pixel Packing nor Default_Phase.
> > Signed-off-by: Sandor Yu <Sandor.yu@nxp.com> > --- > drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c > index 02d8f7e08814..5a7ec066e37a 100644 > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c > @@ -1108,6 +1108,8 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi) > unsigned int output_select = HDMI_VP_CONF_OUTPUT_SELECTOR_PP; > struct hdmi_data_info *hdmi_data = &hdmi->hdmi_data; > u8 val, vp_conf; > + u8 clear_gcp_auto = 0; > + > > if (hdmi_bus_fmt_is_rgb(hdmi->hdmi_data.enc_out_bus_format) || > hdmi_bus_fmt_is_yuv444(hdmi->hdmi_data.enc_out_bus_format) || > @@ -1117,6 +1119,7 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi) > case 8: > color_depth = 4; > output_select = HDMI_VP_CONF_OUTPUT_SELECTOR_BYPASS; > + clear_gcp_auto = 1; > break; > case 10: > color_depth = 5; > @@ -1136,6 +1139,7 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi) > case 0: > case 8: > remap_size = HDMI_VP_REMAP_YCC422_16bit; > + clear_gcp_auto = 1; > break; > case 10: > remap_size = HDMI_VP_REMAP_YCC422_20bit; > @@ -1160,6 +1164,14 @@ 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 (clear_gcp_auto == 1) > + /* disable Auto GCP when 24-bit color */
Maybe add a new define for HDMI_FC_DATAUTO3_GCP_AUTO bit and use it here.
> + val &= ~0x4; > + else > + val |= 0x4; > + hdmi_writeb(hdmi, val, HDMI_FC_DATAUTO3);
Please also add a comment explaining we clear GCP because we only transmit CD and do not handle AVMUTE, PP nor Default_Phase (yet).
> + > hdmi_modb(hdmi, HDMI_VP_STUFF_PR_STUFFING_STUFFING_MODE, > HDMI_VP_STUFF_PR_STUFFING_MASK, HDMI_VP_STUFF); >
Thanks, Neil
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