[PATCH 6.18 323/396] drm/amd/display: Increase HDMI AV mute wait from 2 to 3 frames

6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ray Wu <[email protected]>

commit c216b39fbbc4b007fd6984cffd85039d49a55154 upstream.

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 <[email protected]>
Signed-off-by: Ray Wu <[email protected]>
Tested-by: Dan Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
(cherry picked from commit 0c0d5174b09640d8b560764aa5a177630e076e93)
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c |   16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn30/dcn30_hwseq.c
@@ -837,13 +837,19 @@ void dcn30_set_avmute(struct pipe_ctx *p
 				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);
+			}
 		}
 	}
 }