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

[Gordan Bobic <gordan@bobich.net>]

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.

Gordan