Re: Xen VGA Passthrough - GTX 680 successfully hard-moded to GRID K2

[Gordan Bobic <gordan@bobich.net>]

 On Fri, 27 Sep 2013 13:11:59 -0400, Konrad Rzeszutek Wilk 
 <konrad.wilk@oracle.com> wrote:
> On Mon, Sep 23, 2013 at 07:53:12PM +0100, Gordan Bobic wrote:
>> On 09/23/2013 06:28 PM, David TECHER wrote:
>> >Hi Gordan,
>> >
>> >I wanted to let you know that today I decided to have a try for my 
>> GTX
>> >680. Gigabite GTX 680 2048 MB GDDR5.
>> >
>> >I know that this particular card could be hard-moded to GRID K2 so 
>> VGA
>> >passthrough could work.
>>
>> FYI, GTX680 modified to a K5000 also works fine for VGA passthrough. 
>> I
>> haven't noticed any difference in the functionality.
>>
>> >Following instructions found on
>> 
>> >http://www.eevblog.com/forum/chat/hacking-nvidia-cards-into-their-professional-counterparts/420/
>> >I just removed two resistors.
>>
>> Just out of interest - are your video outputs working correctly? Can
>> you get DL-DVI output or DP output without problems? I find that on
>> bare metal, it works fine, but in a Xen VM, SL-DVI works, but DL-DVI
>> doesn't. DP also works on bare metal, but doesn't work at all domU.
>>
>> As far as I can tell, nobody has had the same issue before. Then
>> again, AFAIK, nobody else is running this setup with an XP64 domU,
>> which is why I am particularly interested to hear if you are seeing
>> the same issue (you mentioned you also run XP64).
>>
>> >I did the test on another VM (Windows 7 64 bits).  I was able to 
>> play
>> >games, shutdown the VM, restart the VM without restarting the dom0.
>> >
>> >I am very impressed. Restarting domU (Linux or Windows) without
>> >restarting the dom0 is very impressive.
>>
>> Indeed. As I have mentioned a number of times before, a faux-Quadro
>> setup is far, far superior to an ATI setup when it comes to VGA
>> passthrough.
>>
>> And I wouldn't say it's impressive per se - it is normal and
>> expected. OTOH, having to reboot dom0 when rebooting domU is utterly
>> broken and unfit for purpose.
>
> I am a bit late to this part - was there an serial output or some 
> other
> way to figure out why dom0 rebooted?

 Because I pressed the reset button? :)
 The dom0 didn't reboot, it just crashed and locked up solid.
 And sorry, no serial output or anything useful in the logs.

 One thing that occurs to me is that this could plausibly have
 been a compound problem in my case, between the usual ATI issues
 and my duff IOMMU hardware (hoping to do some more work on those
 patches soon, but I have a more pressing task of getting some
 updates and testing in place for my RedSleeve Linux distro
 (EL6 for ARM) for a client at the moment).

 Gordan