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authorAric Cyr <aric.cyr@amd.com>2020-05-12 11:48:48 -0400
committerAlex Deucher <alexander.deucher@amd.com>2020-05-27 18:13:14 -0400
commit4e5183200d9b66695c754ef214933402056e7b95 (patch)
tree499c86fa12aa05bb51f93bca22f9a864a97990ee
parentf7d5991b92ff824798693ddf231cf814c9d5a88b (diff)
downloadlinux-sh-4e5183200d9b66695c754ef214933402056e7b95.tar.gz
drm/amd/display: Fix potential integer wraparound resulting in a hang
[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
-rw-r--r--drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c2
1 files changed, 2 insertions, 0 deletions
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);
}