Hybrid Graphics

k0OA1 · n00b Joined: 15 Jul 2014 Posts: 13

Hello,

I'd like to create a virtual machine for video games. I read that it is possible to passthrough a graphics card to the guest OS, on the condition that it is not being used by the host.

This means I need to configure Gentoo so there are two graphics outputs namely Intel HD Graphics 4600 and Nvidia GTX 760.

Right now If I try to use both adapters, only the Nvidia card will output data. This might be because my BIOS requires selection of video output. Or because the intel drivers are not installed or configured in the kernel. Or X is not configured to use the Intel graphics.

I think it would be ok to have a tty shell on the Intel output for launching the guest OS.

Is this possible ?? Do you know how to use both graphics adapters ??

Thank you !!

Al

NeddySeagoon · Posted: Tue Aug 19, 2014 5:15 pm Post subject:

k0OA1,

Different Virtualisation tools offer different facilities.

If you have Intel and nVidia combineh an an Optimus system you do not have two complete graphics systems, you only have one and a half.
Both grapihcs chips can draw into the pixel buffer but only the intel one can read the pixel buffer to the display.

Older, non Optimus systems have two complete graphics systems and a switch so that either can refresh the display.
However, neither system supports independent use of the multiple graphics chips.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

k0OA1 · n00b Joined: 15 Jul 2014 Posts: 13

OK I think I understand :mrgreen:

I figured I would connect both gfx adapters to the monitor and change the input setting to match either adapter when required.
This would mean drivers for Nvidia and Intel running simultaneously. Which isn't possible ?

My system isn't Optimus (it's a desktop).

I decided I would try KVM QEMU. Xen worried me a little with boot grub alterations: I would prefer to launch a window with the guest OS. Maybe it's possible to disable host gfx output and then launch the guest OS with gfx passthrough.

cheers ,

Al

NeddySeagoon · Posted: Tue Aug 19, 2014 9:22 pm Post subject:

k0OA1,

As you have a desktop you can use the graphis cards separately as you wish. They are real separate cards.
The outputs are not switched - they are provided from different connectors.

Almost all of my VMs run headless. I have tried pass through for a four port network card but there is an errata in its on board PCIe bridge chip, so it won,t work.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.