Re: [Qemu-devel] [PATCH] qxl: don't render stuff when the vm is stopped.

[Yonit Halperin]

On 02/15/2012 03:36 PM, Gerd Hoffmann wrote:
> On 02/15/12 14:22, Yonit Halperin wrote:
> > Hi,
> > On 02/15/2012 03:11 PM, Gerd Hoffmann wrote:
> > > This patch fixes the local qxl renderer to not kick spice-server in case
> > > the vm is stopped.  First it is pointless because we render evevything
> > > when the vm is stopped.  Thus there is nothing to render anyway because
> > > a stopped guest can hardly queue more commands.
> > hmm...When the vm is stopped we render only commands that we already
> > read. We don't do more reading from the command ring.
>
> Ah, ok.
>
> > So there may be
> > other pending commands that were not rendered. That is why I
> > suggested allowing rendering when the vm is stopped. But
> > not allowing it during loading the vm during migration.
>
> I'd prefer to keep things simple: let the spice worker run when the
> guest runs, no exceptions.
>
> We may leave some unrendered commands in the ring then.  Ok.  Is that a
> problem for some reason?  Note that the guest may have more commands
> queued which spice-server simply doesn't see yet due to the ring being
> full.  If we stop the guest the wrong moment we can end up with a
> half-done screen update operation no matter what.

Ok. Then ack after correcting the patch comment.

Thanks,
Yonit.
> cheers,
>    Gerd