[PATCH AUTOSEL 5.13 014/189] drm/amd/display: fix potential gpu reset deadlock

Sasha Levin
2021-07-06T11:14:59Z

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

[ Upstream commit cf8b92a75646735136053ce51107bfa8cfc23191 ]

[Why]
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.

[How]
Check if amdgpu executing reset before acquiring dc_lock.

Signed-off-by: Lang Yu <Lang.Yu@amd.com>
Signed-off-by: Roman Li <Roman.Li@amd.com>
Reviewed-by: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@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 652cc1a0e450..875fd187463e 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2726,13 +2726,15 @@ 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);
#ifdef CONFIG_DRM_AMD_DC_HDCP
result = dc_link_handle_hpd_rx_irq(dc_link, &hpd_irq_data, NULL);
#else
result = dc_link_handle_hpd_rx_irq(dc_link, NULL, NULL);
#endif
- mutex_unlock(&adev->dm.dc_lock);
+ if (!amdgpu_in_reset(adev))
+ mutex_unlock(&adev->dm.dc_lock);

out:
if (result && !is_mst_root_connector) {
--
2.30.2