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 b6dc99317d7f8958432f5d4d2e9c2443dcf54964..402d65759e730e2c7e3674f434889991de26c3a8 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
@@ -735,7 +735,7 @@ 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;