[PATCH 12/14] drm/amd/display: Avoid gpio conflict on MST branch

[Wayne Lin]

From: Zhan Liu <zhan.liu at amd.com>

[Why]
Similar to SST branch, gpio conflict also needs to be avoided on
MST. Without doing so, there is a chance that gpio conflict will
occur if multiple gpio interrupts arrive simultaneously.

[How]
By mutex locking/unlocking &aconnector->hpd_lock,
we won't get gpio conflict when handling hpd.

Signed-off-by: Zhan Liu <zhan.liu at amd.com>
Reviewed-by: Bhawanpreet Lakha <bhawanpreet.lakha at amd.com>
Acked-by: Zhan Liu <zhan.liu at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 9dbb9c29c059..23ba35730c7d 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2752,8 +2752,7 @@ static void handle_hpd_rx_irq(void *param)
 	 * conflict, after implement i2c helper, this mutex should be
 	 * retired.
 	 */
-	if (dc_link->type != dc_connection_mst_branch)
-		mutex_lock(&aconnector->hpd_lock);
+	mutex_lock(&aconnector->hpd_lock);
 
 	read_hpd_rx_irq_data(dc_link, &hpd_irq_data);
 
@@ -2822,10 +2821,10 @@ static void handle_hpd_rx_irq(void *param)
 	}
 #endif
 
-	if (dc_link->type != dc_connection_mst_branch) {
+	if (dc_link->type != dc_connection_mst_branch)
 		drm_dp_cec_irq(&aconnector->dm_dp_aux.aux);
-		mutex_unlock(&aconnector->hpd_lock);
-	}
+
+	mutex_unlock(&aconnector->hpd_lock);
 }
 
 static void register_hpd_handlers(struct amdgpu_device *adev)
-- 
2.17.1