Re: [Xen-devel] [Xen VGA Passthrough] Cannot Complete All 3dmark Tests in Windows 8 HVM domU

["Zytaruk, Kelly" <Kelly.Zytaruk@xxxxxxx>]

Gordan,

Thanks for all of the good information.  I am relatively new to providing Xen 
support so I am playing a bit of "catch-up" on some of the issues.  Any 
information you can provide me is useful.

I will present this to our driver development team and see what can be 
determined.

Thanks,
Kelly

> -----Original Message-----
> From: Gordan Bobic [mailto:gordan@xxxxxxxxxx]
> Sent: Thursday, September 18, 2014 5:31 AM
> To: Zytaruk, Kelly; xen-devel@xxxxxxxxxxxxx
> Cc: Hurwitz, Sherry
> Subject: Re: [Xen-devel] [Xen VGA Passthrough] Cannot Complete All 3dmark
> Tests in Windows 8 HVM domU
> 
> On 09/17/2014 06:49 PM, Zytaruk, Kelly wrote:
> > Gordan,
> >
> > Can you tell me exactly what the problem is that you are seeing that 
> > prompted
> you to ask for a bus reset?  I am trying to reproduce your issue but I am not
> having any luck.  I tried a few different scenarios ranging from clean 
> shutdown
> to destroying the domain with 'xl des 5' and restarting.  In all cases I was 
> able to
> cleanly reboot with the graphics driver enabled.
> 
> The issue is quite widely documented in the archives of this list. What 
> happens is
> that upon a domU reboot or shutdown + re-create, one of the following
> happens, usually relatively non-deterministically in terms of what will 
> happen:
> 
> 1) BSOD in the ATI driver.
> 
> 2) domU comes up but the performance is painfully slow and there is corruption
> in the output image, usually manifesting as short white lines on the screen.
> 
> 3) dom0 crash
> 
> and every once in a while with extreme luck
> 
> 4) Works fine - I only saw this happen maybe 5-6 times in all the ATI reboots 
> I
> tried over the months I'd spent trying to work around the issue.
> 
> > I am testing with Win7 as the guest OS with Xen 4.2 and Linux 3.4.9.  
> > Graphics
> card is 'AMD Radeon R9 200' on an AMD Kaveri APU.
> 
> My testing was done on a HD4850, HD6450 and HD7970. HD6450 seemed to
> fare better than the others, possibly because it doesn't have an auxiliary 
> power
> input and is powered purely from the slot. I hypothesised that it might be
> plausible that even though it doesn't report supporting the power states
> required for a PCI level power-off it still works if you manually write the 
> registers
> with setpci. I played with it a bit on the HD6450 and it seemed to work (no
> errors), and the
> HD6450 did seem to come up reliably after a domU reboot much more often
> than the others.
> 
> But I didn't want to spend too much time on investigating that since the
> HD6450 wasn't sufficient for my requirements, so my findings didn't reach a
> conclusion.
> 
> > What are your exact repro steps and are you using any graphics/pci related
> patches.
> 
> I am not using any PCI or graphics related patches. I use Xen 4.3.0 and have 
> been
> using various kernels between 3.8.x and currently 3.14.12. I haven't tried ATI
> cards with kernels more recent than 3.9. Unless you have extra patches in your
> kernel or Xen, I would expect the issue to be very reproducible on Xen 4.2 and
> kernel 3.4.9.
> 
> I'm also pretty sure the ATI reboot issue has been reported a few days ago. 
> The
> manifestation of the problem was display corruption while playing flash 
> videos,
> and it didn't happen on a freshly rebooted dom0.
> 
> Unfortunately, although I have all the parts to build a second machine that is
> exactly the same as my current server for testing and troubleshooting 
> purposes,
> I am not sure when I will be able to get around to doing it. Also, the only 
> spare
> ATI GPU I still have is the HD4850, so any ATI GPU testing I can do will be 
> limited
> to using that.
> 
> Gordan

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