On Tue, May 13, 2025 at 12:18:44PM +0200, Gerd Hoffmann wrote:
> > > diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c
> > > b/drivers/gpu/drm/virtio/virtgpu_drv.c
> > > index e32e680c7197..71c6ccad4b99 100644
> > > --- a/drivers/gpu/drm/virtio/virtgpu_drv.c
> > > +++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
> > > @@ -130,10 +130,10 @@ static void virtio_gpu_remove(struct virtio_device
> > > *vdev)
> > >
> > > static void virtio_gpu_shutdown(struct virtio_device *vdev)
> > > {
> > > - /*
> > > - * drm does its own synchronization on shutdown.
> > > - * Do nothing here, opt out of device reset.
> > > - */
> > > + struct drm_device *dev = vdev->priv;
> > > +
> > > + /* stop talking to the device */
> > > + drm_dev_unplug(dev);
> >
> > I'm not necessarily opposed to using drm_dev_unplug() here, but it's
> > still pretty surprising to me. It's typically used in remove, not
> > shutdown. The typical helper to use at shutdown is
> > drm_atomic_helper_shutdown.
> >
> > So if the latter isn't enough or wrong, we should at least document why.
>
> The intention of this is to make sure the driver stops talking to the
> device (as the comment already says).
>
> There are checks in place in the virt queue functions which will make
> sure the driver will not try place new requests in the queues after
> drm_dev_unplug() has been called. Which why I decided to implement it
> that way.
>
> drm_atomic_helper_shutdown() tears down all outputs according to the
> documentation. Which is something different. I don't think calling
> drm_atomic_helper_shutdown() will do what I need here. Calling it in
> addition to drm_dev_unplug() might make sense, not sure.
>
> Suggestions are welcome.
>
> take care,
> Gerd
I suggest adding comments in code explaining why it's approriate here.
Want to try?
--
MST
