drm/amd/display: Increase HDMI AV mute wait from 2 to 3 frames

Some HDMI sinks need additional GCP packets to properly process the
mute state before the timing generator is disabled, especially after
link re-establishment with HDMI 2.0 scrambling enabled. Waiting for
only 2 frames is insufficient for certain monitor firmware, resulting
in garbled display output on resume from suspend.

Increase the AV mute wait in dcn30_set_avmute() from 2 to 3 frames
to ensure the sink receives enough GCP packets.

Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/5167
Assisted-by: Cursor:Claude-Opus-4.6
Reviewed-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 0c0d5174b09640d8b560764aa5a177630e076e93)
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
index a7c85a2302aba532161f673ff59ce88987142877..2d3587a31bc8b30f0ecef8ac73f52b244aa340ba 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
@@ -847,13 +847,19 @@ void dcn30_set_avmute(struct pipe_ctx *pipe_ctx, bool enable)
                                pipe_ctx->stream_res.stream_enc,
                                enable);
 
-               /* Wait for two frame to make sure AV mute is sent out */
+               /* Wait for three frames to make sure AV mute is sent out.
+                * Some HDMI sinks need additional GCP packets to properly
+                * process the mute state, especially after link re-establishment
+                * with HDMI 2.0 scrambling enabled.
+                */
                if (enable && pipe_ctx->stream_res.tg->funcs->is_tg_enabled(pipe_ctx->stream_res.tg)) {
+                       int i;
+
                        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->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);
+                       for (i = 0; i < 3; i++) {
+                               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);
+                       }
                }
        }
 }