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 f3c682c7fbe6d32d9347fa61f3b337f65965a59f..f0b472e84a53d78d25a7a4b06e004a233b8e2263 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
@@ -781,7 +781,7 @@ 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;