Commit 8de297dc authored Jul 11, 2022 by Aric Cyr Committed by Alex Deucher Jul 25, 2022

drm/amd/display: Avoid MPC infinite loop



[why]
In some cases MPC tree bottom pipe ends up point to itself.  This causes
iterating from top to bottom to hang the system in an infinite loop.

[how]
When looping to next MPC bottom pipe, check that the pointer is not same
as current to avoid infinite loop.

Reviewed-by: Josip Pavic <Josip.Pavic@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

parent 4c5aa594

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -49,6 +49,11 @@ void mpc1_set_bg_color(struct mpc *mpc,

		/* find bottommost mpcc. */
		while (bottommost_mpcc->mpcc_bot) {
		/* avoid circular linked link */
		ASSERT(bottommost_mpcc != bottommost_mpcc->mpcc_bot);
		if (bottommost_mpcc == bottommost_mpcc->mpcc_bot)
		break;

		bottommost_mpcc = bottommost_mpcc->mpcc_bot;
		}