Arch Linux

DrLucky

Member

Registered: 2021-09-21

Posts: 23

Setting default GPU - dual AMD discrete GPU setup

I have 2 AMD GPUs on my host machine, a 580 and a 5700XT. The 580 is in the first PCIe slot (uefi can not set a default GPU, and physically I do not have space to change the 2 around to resolve this.)

My host OS uses the 580 for all of its display outputs, except for one connected to the only working output on the 5700XT.

The 5700xt has the better gpu, of course, and I would like to utilize it for my graphics rendering, Plex decoding, ect.

Most information I can find online about dual GPUs is in reference to vfio passthrough or laptops with an iGPU and descrete GPU. Or in situations with 2 different brand GPUs using 2 different drivers.
Nevertheless, I tried following this from the Arch wiki on Prime https://wiki.archlinux.org/title/PRIME# … offloading
Specifically, I ran

 xrandr --listproviders 

and got an output of

Providers: number : 2
Provider 0: id: 0x59 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 5 associated providers: 1 name:AMD Radeon RX 580 Series @ pci:0000:11:00.0
Provider 1: id: 0xbb cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 4 associated providers: 1 name:AMD Radeon RX 5700 XT @ pci:0000:14:00.0

so I ran

xrandr --setprovideroffloadsink 0xbb 0x59

to set the 5700XT as the provider and the 580 as the sink.
It did not return any errors, however, using a graphical benchmark (Heaven), I can see the 580 is still rendering the benchmark while the 5700xt stays dormant.

Is this the wrong solution/is there a better solution? I thought perhaps something might require me to edit the /etc/X11/xorg.conf.d/20-amdgpu.conf

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,104

Re: Setting default GPU - dual AMD discrete GPU setup

If you just want do redirect things to the more powerful GPU it's "normally" enough to just do DRI_PRIME=1 $programname however since these are technically quite distinct GPU's might want to share/post a xorg log or so to see how it uses the cards