[PATCH 5.9 318/391] drm/amd/display: Increase timeout for DP Disable

From: Greg Kroah-Hartman
Date: Tue Nov 03 2020 - 16:48:59 EST


From: Wesley Chalmers <Wesley.Chalmers@xxxxxxx>

commit 37b7cb10f07c1174522faafc1d51c6591b1501d4 upstream.

[WHY]
When disabling DP video, the current REG_WAIT timeout
of 50ms is too low for certain cases with very high
VSYNC intervals.

[HOW]
Increase the timeout to 102ms, so that
refresh rates as low as 10Hz can be handled properly.

Signed-off-by: Wesley Chalmers <Wesley.Chalmers@xxxxxxx>
Reviewed-by: Aric Cyr <Aric.Cyr@xxxxxxx>
Acked-by: Qingqing Zhuo <qingqing.zhuo@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c
@@ -896,10 +896,10 @@ void enc1_stream_encoder_dp_blank(
*/
REG_UPDATE(DP_VID_STREAM_CNTL, DP_VID_STREAM_DIS_DEFER, 2);
/* Larger delay to wait until VBLANK - use max retry of
- * 10us*5000=50ms. This covers 41.7ms of minimum 24 Hz mode +
+ * 10us*10200=102ms. This covers 100.0ms of minimum 10 Hz mode +
* a little more because we may not trust delay accuracy.
*/
- max_retries = DP_BLANK_MAX_RETRY * 250;
+ max_retries = DP_BLANK_MAX_RETRY * 501;

/* disable DP stream */
REG_UPDATE(DP_VID_STREAM_CNTL, DP_VID_STREAM_ENABLE, 0);