From: Aric Cyr Date: Tue, 12 May 2020 15:48:48 +0000 (-0400) Subject: drm/amd/display: Fix potential integer wraparound resulting in a hang X-Git-Tag: v5.6.16~47 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=be31933db49c8e3d81b96ee6bc9933d2adafe13d;p=thirdparty%2Fkernel%2Fstable.git drm/amd/display: Fix potential integer wraparound resulting in a hang [ Upstream commit 4e5183200d9b66695c754ef214933402056e7b95 ] [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 Reviewed-by: Nicholas Kazlauskas Acked-by: Qingqing Zhuo Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin --- 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 60cea910759bd..0c987b5d68e2b 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 @@ -1651,6 +1651,8 @@ 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); }