[PATCH 6.0 0258/1073] drm/amd/display: wait for vblank during pipe programming

Greg Kroah-Hartman
2022-12-28T15:27:31Z

From: Haiyi Zhou <Haiyi.Zhou@amd.com>

[ Upstream commit 203ccaf586446b578909de1b763278033fb74b51 ]

[WHY]
Skipping vblank during global sync update request can result in
underflow on certain displays.

[HOW]
Roll back to the previous behavior where DC waits for vblank during pipe
programming.

Fixes: 5d3e14421410 ("drm/amd/display: do not wait for vblank during pipe programming")
Tested-by: Mark Broadworth <mark.broadworth@amd.com>
Reviewed-by: Martin Leung <Martin.Leung@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Haiyi Zhou <Haiyi.Zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

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 0f30df523fdf..146189323dbe 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
@@ -1632,10 +1632,8 @@ static void dcn20_program_pipe(
pipe_ctx->pipe_dlg_param.vupdate_width);

if (pipe_ctx->stream->mall_stream_config.type != SUBVP_PHANTOM) {
- pipe_ctx->stream_res.tg->funcs->wait_for_state(
- pipe_ctx->stream_res.tg, CRTC_STATE_VBLANK);
- pipe_ctx->stream_res.tg->funcs->wait_for_state(
- pipe_ctx->stream_res.tg, CRTC_STATE_VACTIVE);
+ pipe_ctx->stream_res.tg->funcs->wait_for_state(pipe_ctx->stream_res.tg, CRTC_STATE_VBLANK);
+ pipe_ctx->stream_res.tg->funcs->wait_for_state(pipe_ctx->stream_res.tg, CRTC_STATE_VACTIVE);
}

pipe_ctx->stream_res.tg->funcs->set_vtg_params(
--
2.35.1