From 6f93f9d06925603a94c2bf0b386e41629e816e0d Mon Sep 17 00:00:00 2001
From: Aric Cyr <aric.cyr@amd.com>
Date: Tue, 12 May 2020 11:48:48 -0400
Subject: drm/amd/display: Fix potential integer wraparound resulting in a hang
Git-commit: 4e5183200d9b66695c754ef214933402056e7b95
Patch-mainline: v5.7
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
[Why]
If VUPDATE_END is before VUPDATE_START the delay calculated can become
very large, causing a soft hang.
[How]
Take the absolute value of the difference between START and END.
Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index 82fc3d5b3b2a..416afb99529d 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -1684,6 +1684,8 @@ static void delay_cursor_until_vupdate(struct dc *dc, struct pipe_ctx *pipe_ctx)
return;
/* Stall out until the cursor update completes. */
+ if (vupdate_end < vupdate_start)
+ vupdate_end += stream->timing.v_total;
us_vupdate = (vupdate_end - vupdate_start + 1) * us_per_line;
udelay(us_to_vupdate + us_vupdate);
}
--
2.28.0