Is it possible to get dual GPUs working in Linux?

Software & Operating Systems Linux
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I’ve got both a 2070 Super and 6900XT. The 2070S has been living in an older rig with a i7 3770. It’s fine. I upgraded the motherboard in my main desktop to an Asus X470-E / 5900X / 64GB of RAM. I think I’ve got the hardware needed to finally do the classic “2 gamers 1 CPU” thing!

Currently I’m using Pop!_OS 21:10 as my primary desktop. I’ve got W10 installed on a separate 512GB SSD, and I have managed to get this install to both dual-boot (for running on bare metal) and in a VM via KVM / Virt-manager / Qemu. But the VM has got no video acceleration. I was hoping that with the 6900XT with SR-IOV support that there was some way to ‘split’ the GPU resources, or better yet, have the VM be able to get the GPU in the host to run 3D acceleration stuff. Ironically it seems there is a janky way to do this with nVidia cards now.

So I decided to YOLO this and just get a motherboard with 3 PCIe slots and stick my spare 2070 Super in it, and get the CUDA cores for acceleration in Blender (since the Linux version does not support AMD GPUs anymore?), have more Etherium mining horsepower, and the ability to unload the nvidia driver and pass it through to the windows VM and get Windows software and gaming compatibility for those times where I do need that.

Is this possible? If I install the nvidia 510 proprietary driver, the system will not load SDDM or any graphics desktop manager. Not really sure what the issue is. I just end up with black screens on my monitors. If I purge all things nVidia then I can get SDDM to load along with desktop of choice (KDE Plasma or Gnome)

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Yes but you are not going to like it. #1 you can’t use Pop_OS…or anything GTK. GTK is broken by design for dual GPU/Multi XScreen since GTK3.

You also can’t accept the default xrandr style set up, you will have to use X11 and create a proper xorg.conf. Which is also to say Wayland is also useless and always will be by design.

If by VM you mean Qemu for passthrough that’s a different set up and I’ve got not experience with it because WINE works for everything I run.

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Hol up; why does this hardware configuration work fine in laptops with optimus / PRIME / bumblebee (whatever they are calling it now)? I’ve got a HP Omen with Ryzen 4800H w/ integrated vega graphics and discrete 1660 Ti GPU. I don’t think it features a hardware MUX, so how is that configuration any different than what I’ve got going on with my desktop?

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Are you running separate XScreens? :stuck_out_tongue: Multi GPU will work with GTK under the right caveats which mean no GPU delegation, bad performance and no XScreens to name a few. Dual laptop/hybrid are basically a “one at a time” situation…not the same. Even if you run real hybrid that is normally done with a second X session which side steps the issue, adds overhead and reduces performance and seamless use.