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

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Message-Id: <20201103203408.568136235@linuxfoundation.org>
Date:   Tue,  3 Nov 2020 21:36:09 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Wesley Chalmers <Wesley.Chalmers@....com>,
        Aric Cyr <Aric.Cyr@....com>,
        Qingqing Zhuo <qingqing.zhuo@....com>,
        Alex Deucher <alexander.deucher@....com>
Subject: [PATCH 5.9 318/391] drm/amd/display: Increase timeout for DP Disable

From: Wesley Chalmers <Wesley.Chalmers@....com>

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@....com>
Reviewed-by: Aric Cyr <Aric.Cyr@....com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Cc: <stable@...r.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 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);