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[AMD Official Use Only - Internal Distribution Only]
right, that makes more sense. I will post a v2 shortly
From: Kazlauskas, Nicholas <Nicholas.Kazlauskas@xxxxxxx>
Sent: January 11, 2021 3:22 PM To: Lakha, Bhawanpreet <Bhawanpreet.Lakha@xxxxxxx>; Chen, Guchun <Guchun.Chen@xxxxxxx>; Deucher, Alexander <Alexander.Deucher@xxxxxxx> Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx <amd-gfx@xxxxxxxxxxxxxxxxxxxxx> Subject: Re: [PATCH] drm/amd/display: Fix deadlock during gpu reset 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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