Re: [PATCH v2 7/7] drm/panfrost: Explicitly enable MMU interrupts at device init

["Adrián Larumbe" <adrian.larumbe@collabora.com>]

On 05.06.2026 08:56, Boris Brezillon wrote:
> On Thu, 04 Jun 2026 18:35:26 +0100
> Adrián Larumbe <adrian.larumbe@collabora.com> wrote:
> 
> > Because the device must be in a position to accept jobs between the time
> > drm_dev_register() is called and autosuspend first kicks in, there's a very
> > narrow window inbetween during which jobs targeting the tiler buffer
> > object would time out, since the device's PM status is 'Active', but no MMU
> > interrupts were enabled at device initialisation time.
> > 
> > Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
> > Fixes: 73e467f60acd ("drm/panfrost: Consolidate reset handling")
> > ---
> >  drivers/gpu/drm/panfrost/panfrost_mmu.c | 11 +++++++++--
> >  drivers/gpu/drm/panfrost/panfrost_mmu.h |  2 ++
> >  2 files changed, 11 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> > index 4a3162c3b659..0e1ad6256c2c 100644
> > --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
> > +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> > @@ -336,6 +336,12 @@ void panfrost_mmu_as_put(struct panfrost_device *pfdev, struct panfrost_mmu *mmu
> >  	WARN_ON(atomic_read(&mmu->as_count) < 0);
> >  }
> >  
> > +void panfrost_mmu_enable_interrupts(struct panfrost_device *pfdev)
> > +{
> > +	mmu_write(pfdev, MMU_INT_CLEAR, ~0);
> > +	mmu_write(pfdev, MMU_INT_MASK, ~0);
> > +}
> > +
> >  void panfrost_mmu_reset(struct panfrost_device *pfdev)
> >  {
> >  	struct panfrost_mmu *mmu, *mmu_tmp;
> > @@ -355,8 +361,7 @@ void panfrost_mmu_reset(struct panfrost_device *pfdev)
> >  
> >  	spin_unlock(&pfdev->as_lock);
> >  
> > -	mmu_write(pfdev, MMU_INT_CLEAR, ~0);
> > -	mmu_write(pfdev, MMU_INT_MASK, ~0);
> > +	panfrost_mmu_enable_interrupts(pfdev);
> >  }
> >  
> >  static size_t get_pgsize(u64 addr, size_t size, size_t *count)
> > @@ -970,6 +975,8 @@ int panfrost_mmu_init(struct panfrost_device *pfdev)
> >  		return err;
> >  	}
> >  
> > +	panfrost_mmu_enable_interrupts(pfdev);
> > +
> >  	return 0;
> >  }
> >  
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.h b/drivers/gpu/drm/panfrost/panfrost_mmu.h
> > index 27c3c65ed074..3140eb4fea0f 100644
> > --- a/drivers/gpu/drm/panfrost/panfrost_mmu.h
> > +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.h
> > @@ -12,6 +12,8 @@ struct panfrost_mmu;
> >  int panfrost_mmu_map(struct panfrost_gem_mapping *mapping);
> >  void panfrost_mmu_unmap(struct panfrost_gem_mapping *mapping);
> >  
> > +void panfrost_mmu_enable_interrupts(struct panfrost_device *pfdev);
> 
> You don't need to expose this function, it's only used inside
> panfrost_mmu.c.

Will remove in the next revision.

> > +
> >  int panfrost_mmu_init(struct panfrost_device *pfdev);
> >  void panfrost_mmu_fini(struct panfrost_device *pfdev);
> >  void panfrost_mmu_reset(struct panfrost_device *pfdev);
> > 

Adrian Larumbe