Re: [PATCH v4 04/12] virtio: console: Add freeze and restore handlers to support S4

[Amit Shah <amit.shah@redhat.com>]

On (Wed) 07 Dec 2011 [12:43:24], Michael S. Tsirkin wrote:

> > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
> > index e14f5aa..fd2fd6f 100644
> > --- a/drivers/char/virtio_console.c
> > +++ b/drivers/char/virtio_console.c
> > @@ -1844,6 +1844,60 @@ static unsigned int features[] = {
> >  	VIRTIO_CONSOLE_F_MULTIPORT,
> >  };
> >  
> > +#ifdef CONFIG_PM
> > +static int virtcons_freeze(struct virtio_device *vdev)
> > +{
> > +	struct ports_device *portdev;
> > +	struct port *port;
> > +
> > +	portdev = vdev->priv;
> > +
> > +	vdev->config->reset(vdev);
> 
> 
> So here, cancel_work_sync might still be running.
> If it does run, might it try to access the device
> config?  Could not determine this quickly, if yes it's a problem.

Similar to the other comment: I don't see why just resetting device
can cause config queue access to go bad.

		Amit