Re: [Xen-devel] [Xen-users] VGA passthough still not working

[Doug Magee <djmagee@xxxxxxxxxxxx>]

On Tue, 2012-01-24 at 09:37 -0500, Tobias Geiger wrote:
> > > > Both setup have the "flaw" that they only work once - meaning
> you
> > >
> > > can't reboot
> > >
> > > > your DomU , cause after the reboot the passed-through Card
> doesnt
> > >
> > > have correct
> > >
> > > > 3D-Accelleration any more (was/is the case with NVIDIA and ATI,
> > >
> > > Windows XP and
> > >
> > > > Windows7 )
> > >
> > > For me it was with ATI with Windows7. Hadn't tried other OSes.
> > >
> > > Anybody had luck with passing the card more than once to a guest?
> With
> > > any random set of patches?
> >
> 
> I was a bit un-percice regarding the "reboot" issue:
> 
> The passing-through itself works even after a reboot of DomU - the
> rebooted
> System spits out its Graphics normaly through the passed-through Card
> (NVIDA
> or ATI doesnt matter here) ; BUT:
> After a reboot it doesn't work properly. Meaning: Slow 3d Performance,
> i.e.
> unsable for real 3d apps, even a 3d Desktop;
> For example, when the Card gives you 70fps in a Benchmark after a
> fresh Cold
> Boot, it only gives you 5-10fps after a reboot, this will be that low
> until
> you reboot Dom0 also, not only DomU;
> 
> hopefully i described the scenario better now...
> 

Ah, got it.  I hadn't been doing anything 3D intensive, only running the
Aero desktop.  I installed 3DMark Vantage and ran a couple of tests.  I
get the same results (within a fraction of a %) after a cold boot as i
do after rebooting multiple times, and always very close to native.  It
seems i don't have the problem you're having.

Do you get any different log messages after a reboot (xl dmesg, dom0
dmesg, qemu log)?  Have you tried with iommu=verbose to see if there's
any more useful information there?

> 
> > Yes, I've had a machine running for a couple of weeks, hosting a
> Windows
> > 7 domu with a passed-through Radeon 4770.  I've rebooted the virtual
> > machine multiple times, as well as gone through a couple of xl
> > destroy/create cycles.
> >
> > I only pass it through as a secondary card, as I have the IGD as the
> > primary on the host.  The machine is a DQ67SW with a Core i5.  This
> is
> > running xen-unstable (c/s 24465) on a 3.2.1 dom0, with no extra
> patches.
> >
> > I haven't, however, had any luck passing through the IGD to anything
> > other than a Windows XP, and that includes running the latest
> qemu-xen
> > with Jean's patches (opregion, host bridge config space mapping).
> I've
> > been intending to start a separate thread for that...
> 
> 
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> 
> 



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