Nvidia modules and kernel versions

[cmprior]

Hi
Can anyone tell me if I can uninstall the NVidia module for a specific kernel version whilst retaining it for other kernel versions?
I am having problems using Wayland with the Nvidia drivers (works fine with X11) and want to see if the Nouveau driver can work for Wayland. I'd like to try this without losing a working kernel version if possible. I'm guessing I'll have to play with the blacklist options in modules.conf as well.
I've attempted to follow the wiki for having both drivers installed at the same time and switching between them using grub options but this didn't seem to work - I ended up having Nvidia running in every case, with nouveau as well at times - which caused all sorts of problems.
System is x86_64, nvidia 470. version due to age of graphics card. Have just installed the latest stable kernel.
kde plasma latest stable version

Thanks

Chris

[Ionen]

By default portage already does not remove modules for old kernel versions (even if you remove nvidia-drivers), albeit if you want your system to work the nvidia user space libraries (also installed by nvidia-drivers) need to be present and their version match the with the modules.

That aside, you don't need to remove nvidia-drivers to try nouveau, just edit /etc/modprobe.d/nvidia.conf and comment out "blacklist nouveau" and the kernel "should" load nouveau first and nvidia will be unable to remove it (or at least, legacy drivers can't, newer ones have an optional way), uncomment if want to go back (possibly from a rescue media if something went badly). A dual kernel route could be to have one kernel with the nouveau modules and one without, optionally builtin if want to ignore blacklist, and the kernel without nouveau would still use nvidia-drivers. I think there is a way to disable or blacklist nouveau from the kernel commandline allowing to share kernels without changing nvidia.conf every time, but I never tried myself. Doing more than edit nvidia.conf feels kind of messy if you just want to try it though...

Note that nouveau typically has poor performance due to being unable to reclock cards (aka, they're left in low power mode), Vulkan support is also rather early stages. Albeit if all you want is a display (and not intensive games), then it's fine. Right now 470 is still supported by nvidia, so there's no hurry to switch to nouveau though.

On another note, 470 technically has wayland support but is so broken that we removed USE=wayland at this point. 470 notably never supported GBM, and software support for the alternative (EGLStream) is not quite there and has been bitrotting over the years. So if want to use 470 you'll be with Xorg until you get new hardware, which imo is fine.. Xorg is not going anywhere anytime soon.