Re: [PATCH 1/3] drm/panthor: Call panthor_gpu_coherency_init() after PM resume()

[Boris Brezillon <boris.brezillon@collabora.com>]

On Tue, 1 Apr 2025 17:17:40 +0100
Liviu Dudau <liviu.dudau@arm.com> wrote:

> On Tue, Apr 01, 2025 at 09:57:08AM +0200, Boris Brezillon wrote:
> > When the device is coherent, panthor_gpu_coherency_init() will read
> > GPU_COHERENCY_FEATURES to make sure the GPU supports the ACE-Lite
> > coherency protocol, which will fail if the clocks/power-domains are
> > not enabled when the read is done. Move the
> > panthor_gpu_coherency_init() call after the device has been resumed
> > to prevent that.  
> 
> While doing this, do you mind fixing the definitions for GPU_COHERENCY_ACE
> and GPU_COHERENCY_ACE_LITE? They are swapped, according to my arch spec.

Oh, nice catch! I'll add a patch fixing that in v2.

> 
> Otherwise, patch looks good to me.
> 
> Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
> 
> Best regards,
> Liviu
> 
> > 
> > Fixes: dd7db8d911a1 ("drm/panthor: Explicitly set the coherency mode")
> > Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> > ---
> >  drivers/gpu/drm/panthor/panthor_device.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
> > index a9da1d1eeb70..c73c1608d6e6 100644
> > --- a/drivers/gpu/drm/panthor/panthor_device.c
> > +++ b/drivers/gpu/drm/panthor/panthor_device.c
> > @@ -171,10 +171,6 @@ int panthor_device_init(struct panthor_device *ptdev)
> >  	struct page *p;
> >  	int ret;
> >  
> > -	ret = panthor_gpu_coherency_init(ptdev);
> > -	if (ret)
> > -		return ret;
> > -
> >  	init_completion(&ptdev->unplug.done);
> >  	ret = drmm_mutex_init(&ptdev->base, &ptdev->unplug.lock);
> >  	if (ret)
> > @@ -247,6 +243,10 @@ int panthor_device_init(struct panthor_device *ptdev)
> >  	if (ret)
> >  		goto err_rpm_put;
> >  
> > +	ret = panthor_gpu_coherency_init(ptdev);
> > +	if (ret)
> > +		return ret;
> > +
> >  	ret = panthor_mmu_init(ptdev);
> >  	if (ret)
> >  		goto err_unplug_gpu;
> > -- 
> > 2.48.1
> >   
>