Commit 68eb3ae3 authored by Werner Sembach's avatar Werner Sembach Committed by Alex Deucher
Browse files

drm/amd/display: Try YCbCr420 color when YCbCr444 fails 



When encoder validation of a display mode fails, retry with less bandwidth
heavy YCbCr420 color mode, if available. This enables some HDMI 1.4 setups
to support 4k60Hz output, which previously failed silently.

On some setups, while the monitor and the gpu support display modes with
pixel clocks of up to 600MHz, the link encoder might not. This prevents
YCbCr444 and RGB encoding for 4k60Hz, but YCbCr420 encoding might still be
possible. However, which color mode is used is decided before the link
encoder capabilities are checked. This patch fixes the problem by retrying
to find a display mode with YCbCr420 enforced and using it, if it is
valid.

Reviewed-by: default avatarHarry Wentland <harry.wentland@amd.com>
Signed-off-by: default avatarWerner Sembach <wse@tuxedocomputers.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent bb01091c

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

+9 −0
Original line number Diff line number Diff line
@@ -6161,6 +6161,15 @@ create_validate_stream_for_sink(struct amdgpu_dm_connector *aconnector, 


	} while (stream == NULL && requested_bpc >= 6);



	if (dc_result == DC_FAIL_ENC_VALIDATE && !aconnector->force_yuv420_output) {

		DRM_DEBUG_KMS("Retry forcing YCbCr420 encoding\n");



		aconnector->force_yuv420_output = true;

		stream = create_validate_stream_for_sink(aconnector, drm_mode,

						dm_state, old_stream);

		aconnector->force_yuv420_output = false;

	}



	return stream;

}