From: Josip Pavic <Josip.Pavic@xxxxxxx>
[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: Jun Lei <Jun.Lei@xxxxxxx>
Acked-by: Tom Chung <chiahsuan.chung@xxxxxxx>
Signed-off-by: Josip Pavic <Josip.Pavic@xxxxxxx>
---
drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c | 6 ++++++
drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c | 6 ++++++
2 files changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c
index 769974375b4b..8e9384094f6d 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_mpc.c
@@ -131,6 +131,12 @@ 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;
diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c
index 3d307dd58e9a..116f67a0b989 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c
@@ -531,6 +531,12 @@ static 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;
--
2.25.1
