On Wed, Mar 17, 2021 at 11:25 AM Werner Sembach wse@tuxedocomputers.com wrote:
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.
Signed-off-by: Werner Sembach wse@tuxedocomputers.com Cc: stable@vger.kernel.org
This seems reasonable to me. Harry, Leo, Any objections?
Alex
From c9398160caf4ff20e63b8ba3a4366d6ef95c4ac3 Mon Sep 17 00:00:00 2001 From: Werner Sembach wse@tuxedocomputers.com Date: Wed, 17 Mar 2021 12:52:22 +0100 Subject: [PATCH] Retry forcing YCbCr420 color on failed encoder validation
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 961abf1cf040..2d16389b5f1e 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -5727,6 +5727,15 @@ 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;}
-- 2.25.1
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