> -----Original Message----- > From: Neil Armstrong <narmstrong@xxxxxxxxxxxx> > Sent: 2022年4月8日 20:40 > To: Sandor Yu <sandor.yu@xxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; andrzej.hajda@xxxxxxxxx; > robert.foss@xxxxxxxxxx; Laurent.pinchart@xxxxxxxxxxxxxxxx; > jonas@xxxxxxxxx; jernej.skrabec@xxxxxxxxx; hverkuil-cisco@xxxxxxxxx > Cc: S.J. Wang <shengjiu.wang@xxxxxxx>; cai.huoqing@xxxxxxxxx; > maxime@xxxxxxxxxx; harry.wentland@xxxxxxx > Subject: [EXT] Re: [PATCH v2 3/5] drm: bridge: dw_hdmi: Enable GCP only for > Deep Color > > Caution: EXT Email > > 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@xxxxxxx> > > --- > > 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. OK, I will add it. > > > + 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). > OK. Sandor > > + > > hdmi_modb(hdmi, > HDMI_VP_STUFF_PR_STUFFING_STUFFING_MODE, > > HDMI_VP_STUFF_PR_STUFFING_MASK, > HDMI_VP_STUFF); > > > > Thanks, > Neil
