Re: [PATCH v2] virtio: only reset device and restore status if needed in device resume

[Jason Wang <jasowang@xxxxxxxxxx>]

On Wed, Nov 6, 2024 at 5:29 PM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote:
>
> On Fri, Nov 01, 2024 at 10:11:11AM +0800, Jason Wang wrote:
> > On Fri, Nov 1, 2024 at 9:54 AM <qiang4.zhang@xxxxxxxxxxxxxxx> wrote:
> > >
> > > From: Qiang Zhang <qiang4.zhang@xxxxxxxxx>
> > >
> > > Virtio core unconditionally reset and restore status for all virtio
> > > devices before calling restore method. This breaks some virtio drivers
> > > which don't need to do anything in suspend and resume because they
> > > just want to keep device state retained.
> >
> > The challenge is how can driver know device doesn't need rest.
>
> I actually don't remember why do we do reset on restore. Do you?
>

Because the driver doesn't know if the device can keep its state, so
it chooses to start from that.

Thanks