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

[Gerd Hoffmann]

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.

cheers,
  Gerd