From d438d113380eff1c27a1d239a9bd624e0fb15b6d Mon Sep 17 00:00:00 2001 From: Nikola Cornij Date: Thu, 28 Mar 2019 13:47:25 -0400 Subject: [PATCH] drm/amd/display: Use 1/8th DSC target bitrate precision for N4:2:2 and 4:2:0 formats [why] On at least some of the devices (e.g. Realtek scaler) we get a black screen if 1/16th precision is used. [how] Work around it by reducing precision to 1/8th for N4:2:2 and 4:2:0 color formats. This is a safe workaround and would have a very mild impact on the quality. The issue is still to be root-caused and fixed correctly. Signed-off-by: Nikola Cornij Reviewed-by: Wenjing Liu Acked-by: Bhawanpreet Lakha Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c index 471eb9873885..c649f62d183d 100644 --- a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c +++ b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c @@ -228,6 +228,10 @@ static bool dc_intersect_dsc_caps( dsc_common_caps->bpp_increment_div = min(dsc_sink_caps->bpp_increment_div, dsc_enc_caps->bpp_increment_div); + // TODO DSC: Remove this workaround for N422 and 420 once it's fixed, or move it to get_dsc_encoder_caps() + if (pixel_encoding == PIXEL_ENCODING_YCBCR422 || pixel_encoding == PIXEL_ENCODING_YCBCR420) + dsc_common_caps->bpp_increment_div = min(dsc_common_caps->bpp_increment_div, (uint32_t)8); + return true; }