Re: [Qemu-devel] [PATCH 2/2] qxl: add QXL_IO_UPDATE_MEM for guest S3&S4 support

[Alon Levy]

On Mon, Jun 20, 2011 at 05:11:07PM +0200, Alon Levy wrote:
> On Mon, Jun 20, 2011 at 04:07:59PM +0200, Gerd Hoffmann wrote:
> > >>What is the difference to one worker->stop() + worker->start() cycle?
> > >>
> > >
> > >ok, stop+start won't disconnect any clients either. But does stop render 
> > >all waiting commands?
> > >I'll have to look, I don't know if it does.
> > 
> > It does.  This is what qemu uses to flush all spice server state to
> > device memory on migration.
> > 
> > What is the reason for deleting all surfaces?
> 
> Making sure all references are dropped to pci memory in devram. We would need 
> to recreate all
> the surfaces after reset anyway.

That's not right. The reason is that for the windows driver I don't know
if this is a resolution change or a suspend. So it was easier to destroy all 
the surfaces and then the two cases are equal - before going to sleep / leaving 
the current resolution I destroy all the surfaces, when coming back I recreate 
the surfaces. If it's a resolution change there is no coming back stage, but 
since all surfaces are destroyed there is no error when the same surface id's 
are reused.

> 
> > 
> > cheers,
> >   Gerd
> > 
>