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Commit a06e4eb6 authored by Josip Pavic's avatar Josip Pavic Committed by Greg Kroah-Hartman
Browse files

drm/amd/display: Avoid MPC infinite loop 



[ Upstream commit 8de297dc046c180651c0500f8611663ae1c3828a ]

[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: default avatarJosip Pavic <Josip.Pavic@amd.com>
Reviewed-by: default avatarJun Lei <Jun.Lei@amd.com>
Acked-by: default avatarAlex Hung <alex.hung@amd.com>
Signed-off-by: default avatarAric Cyr <aric.cyr@amd.com>
Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 2608885a

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

+6 −0
Original line number Diff line number Diff line
@@ -118,6 +118,12 @@ struct mpcc *mpc1_get_mpcc_for_dpp(struct mpc_tree *tree, int dpp_id) 
	while (tmp_mpcc != NULL) {

		if (tmp_mpcc->dpp_id == dpp_id)

			return tmp_mpcc;



		/* avoid circular linked list */

		ASSERT(tmp_mpcc != tmp_mpcc->mpcc_bot);

		if (tmp_mpcc == tmp_mpcc->mpcc_bot)

			break;



		tmp_mpcc = tmp_mpcc->mpcc_bot;

	}

	return NULL;

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c

+6 −0
Original line number Diff line number Diff line
@@ -488,6 +488,12 @@ struct mpcc *mpc2_get_mpcc_for_dpp(struct mpc_tree *tree, int dpp_id) 
	while (tmp_mpcc != NULL) {

		if (tmp_mpcc->dpp_id == 0xf || tmp_mpcc->dpp_id == dpp_id)

			return tmp_mpcc;



		/* avoid circular linked list */

		ASSERT(tmp_mpcc != tmp_mpcc->mpcc_bot);

		if (tmp_mpcc == tmp_mpcc->mpcc_bot)

			break;



		tmp_mpcc = tmp_mpcc->mpcc_bot;

	}

	return NULL;