drm/amd/display: Subsample mode suboptimal for YCbCr4:2:2 (e6d14df7) · Commits · 戴 / test

[Why&How] Driver defaults to 1-tap subsample mode for 4:2:2. DCE11.2 added 3-tap. The policy is: DCE8-DCE11 - change to 2-tap, it's better than 1-tap. DCE11.2+ - use 3-tap Note that 4:2:0 was added in DCE11.2 and already uses 3-tap always. Note 2 is that DCE not covered on Linux, only DCN+ Signed-off-by:

Krunoslav Kovac <Krunoslav.Kovac@amd.com> Reviewed-by:

Charlene Liu <Charlene.Liu@amd.com> Acked-by:

Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com> Signed-off-by:

Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_opp.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -168,7 +168,10 @@ static void opp1_set_pixel_encoding(
		REG_UPDATE(FMT_CONTROL, FMT_PIXEL_ENCODING, 0);
		break;
		case PIXEL_ENCODING_YCBCR422:
		REG_UPDATE(FMT_CONTROL, FMT_PIXEL_ENCODING, 1);
		REG_UPDATE_3(FMT_CONTROL,
		FMT_PIXEL_ENCODING, 1,
		FMT_SUBSAMPLING_MODE, 2,
		FMT_CBCR_BIT_REDUCTION_BYPASS, 0);
		break;
		case PIXEL_ENCODING_YCBCR420:
		REG_UPDATE(FMT_CONTROL, FMT_PIXEL_ENCODING, 2);

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_opp.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -116,6 +116,8 @@
		type FMT_RAND_G_SEED; \
		type FMT_RAND_B_SEED; \
		type FMT_PIXEL_ENCODING; \
		type FMT_SUBSAMPLING_MODE; \
		type FMT_CBCR_BIT_REDUCTION_BYPASS; \
		type FMT_CLAMP_DATA_EN; \
		type FMT_CLAMP_COLOR_FORMAT; \
		type FMT_DYNAMIC_EXP_EN; \

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