Hi, > -----Original Message----- > From: Neil Armstrong <narmstrong@xxxxxxxxxxxx> > Sent: 2022年4月6日 17:20 > 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 > Cc: S.J. Wang <shengjiu.wang@xxxxxxx>; cai.huoqing@xxxxxxxxx; > maxime@xxxxxxxxxx; harry.wentland@xxxxxxx; hverkuil-cisco@xxxxxxxxx; > amuel@xxxxxxxxxxxx > Subject: [EXT] Re: [PATCH v1 3/5] drm: bridge: dw_hdmi: Enable GCP only for > Deep Color > > Caution: EXT Email > > On 06/04/2022 10:48, Sandor.yu@xxxxxxx wrote: > > From: Sandor Yu <Sandor.yu@xxxxxxx> > > > > 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 <Sandor.yu@xxxxxxx> > > --- > > 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); > > > > Do you handle the case when color_depth == 0 when output is YUV422 ? For YUV422 color depth 8, the gcp_auto bit need clear too, I will add it. > > Neil Thanks, Sandor
