drm/amd/display: Fix 'failed to blank crtc!'

[ Upstream commit 01f60348d8fb6b3fbcdfc7bdde5d669f95b009a4 ]

[why]
DCN35 is having “DC: failed to blank crtc!” when running HPO
test cases. It's caused by not having sufficient udelay time.

[how]
Replace the old wait_for_blank_complete function with fsleep function to
sleep just until the next frame should come up. This way it doesn't poll
in case the pixel clock or other clock was bugged or until vactive and
the vblank are hit again.

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Wen Chen <Wen.Chen3@amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
index d8cf5f20ef3bdab1b9e9400db001e608e059d95a..d252d10c81347100b2c4e93f8055641e7c7d9891 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
@@ -757,7 +757,7 @@ enum dc_status dcn20_enable_stream_timing(
                return DC_ERROR_UNEXPECTED;
        }
 
-       hws->funcs.wait_for_blank_complete(pipe_ctx->stream_res.opp);
+       fsleep(stream->timing.v_total * (stream->timing.h_total * 10000u / stream->timing.pix_clk_100hz));
 
        params.vertical_total_min = stream->adjust.v_total_min;
        params.vertical_total_max = stream->adjust.v_total_max;