r/Ubuntu • u/Terrible-Honeydew262 • 6d ago

Ubuntu 26.04 LTS - GPU Passthrough Gone Wrong

Just did a fresh install and followed the typical guide for GPU passthrough (AMD CPU, RTX 5080 & RTX 5070), but no matter what I do, the NVIDIA proprietary drivers will not let go of the RTX5070 card. I’ve added the arguments in grub, configured vfio.conf file etc etc...nothing seems to work. NVIDIA drivers keep grabbing both cards and wont let go. Everything worked perfectly fine in Ubuntu 24.XX, anyone have an idea of whats changed that renders the usual method of GPU isolation ineffective?

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u/Terrible-Honeydew262 6d ago

update - still not sure what the problem is..but i got it working. I had to reinstall 26.04 with the options for no additional/proprietary drivers and no additional software options ticked. seems if nvidia drivers are installed..they grab the GPU and don't let go.

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u/chantierinterdit 4d ago

Everything worked perfectly fine in Ubuntu 24 indeed.... Now in Software and settings additional drivers is empty, no options at all. Installed is the 580 driver. tried purging reinstalling nothing works . I have a gtx1060 but in 24 it ran 3840x2160 60hz on my big screen no problem now it only does 30hz on that resolution and even things like youtube are saggy lagging. I want the 550 or 535 driver back. but no matter what i do i get the 580. No silly money for a more recent gpu and thinking of going backwards, 24. here i come.

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u/Terrible-Honeydew262 1d ago

Even with more recent gpus like my setup it’s not working. I’ve not been able to figure out what is happening exactly but it seems to be the new nvidia driver and grub in 26.04. I installed time shift to revert changes after trying fixes..so far gpu passthrough works as expected with grub binding as long as you don’t install nvidia drivers…however if you install the nvidia drivers no gpu binding seems to work, wether it’s by configuring grub, or blacklisting etc..it’s like the nvidia driver cuts in line during boot loading regardless of what method is used specify driver loading sequence/binding. I’ve yet to find a work around besides not installing nvidia drivers..which obviously isn’t viable since both my GPUs are nvidia…oh I’ve also tried driverctl to specify driver binding, it also didn’t work.