[PATCH AUTOSEL 5.12 011/160] drm/amd/display: fix potential gpu reset deadlock

Sasha Levin sashal at kernel.org
Tue Jul 6 11:15:57 UTC 2021

From: Roman Li <Roman.Li at amd.com>

[ Upstream commit cf8b92a75646735136053ce51107bfa8cfc23191 ]

In gpu reset dc_lock acquired in dm_suspend().
Asynchronously handle_hpd_rx_irq can also be called
through amdgpu_dm_irq_suspend->flush_work, which also
tries to acquire dc_lock. That causes a deadlock.

Check if amdgpu executing reset before acquiring dc_lock.

Signed-off-by: Lang Yu <Lang.Yu at amd.com>
Signed-off-by: Roman Li <Roman.Li at amd.com>
Reviewed-by: Qingqing Zhuo <Qingqing.Zhuo at amd.com>
Acked-by: Wayne Lin <Wayne.Lin at amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 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 eed494630583..d95569e0e53a 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2624,13 +2624,15 @@ static void handle_hpd_rx_irq(void *param)
-	mutex_lock(&adev->dm.dc_lock);
+	if (!amdgpu_in_reset(adev))
+		mutex_lock(&adev->dm.dc_lock);
 	result = dc_link_handle_hpd_rx_irq(dc_link, &hpd_irq_data, NULL);
 	result = dc_link_handle_hpd_rx_irq(dc_link, NULL, NULL);
-	mutex_unlock(&adev->dm.dc_lock);
+	if (!amdgpu_in_reset(adev))
+		mutex_unlock(&adev->dm.dc_lock);
 	if (result && !is_mst_root_connector) {

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