On 2021-01-11 2:55 p.m., Bhawanpreet Lakha wrote:
[Why]
during idle optimizations we acquire the dc_lock, this lock is also
acquired during gpu_reset so we end up hanging the system due to a
deadlock
[How]
If we are in gpu reset dont acquire the dc lock, as we already have it
Are we sure this is the behavior we want?
I think if we are in GPU reset then we shouldn't be attempting to modify
idle optimization state at all, ie. return early if amdgpu_in_reset.
The calls around the locks are working around bad policy.
Regards,
Nicholas Kazlauskas
Fixes: 06d5652541c3 ("drm/amd/display: enable idle optimizations for linux (MALL stutter)")
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@xxxxxxx>
---
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 99c7f9eb44aa..2170e1b2d32c 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -5556,7 +5556,8 @@ static inline int dm_set_vblank(struct drm_crtc *crtc, bool enable)
if (!dc_interrupt_set(adev->dm.dc, irq_source, enable))
return -EBUSY;
- mutex_lock(&dm->dc_lock);
+ if (!amdgpu_in_reset(adev))
+ mutex_lock(&dm->dc_lock);
if (enable)
dm->active_vblank_irq_count++;
@@ -5568,7 +5569,8 @@ static inline int dm_set_vblank(struct drm_crtc *crtc, bool enable)
DRM_DEBUG_DRIVER("Allow idle optimizations (MALL): %d\n", dm->active_vblank_irq_count == 0);
- mutex_unlock(&dm->dc_lock);
+ if (!amdgpu_in_reset(adev))
+ mutex_unlock(&dm->dc_lock);
return 0;
}
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