How can I instruct my kernels to use different X drivers based on kernel version?
 

Hello, I have a rather weird questions.

I'm trying to work with XEN virtualization and I need to boot into a kernel (compiled it myself) using a different set of gpu drivers than usual. I have an nVidia GTX570 which uses proprietary nVidia drivers (Which don't work in XEN).

I want to get rid on these drivers for just one kernel, for the other kernel (which currently works) I want to keep the nVidia ones.

I know it's not simple and it wouldn't be manual, but I want to be able to swap the drivers around when I need to boot into one or the other kernel.
Following these:
https://trisquel.info/en/forum/how-i...nvidia-drivers
http://nouveau.freedesktop.org/wiki/InstallNouveau
http://us.download.nvidia.com/XFree8...alldriver.html
I realized I have to:
1) build a different libdrm for nouveau drivers
2) swap the old and new libdrm depending on which kernel I need to boot
3) not install the nvidia kernel module (nvidia.ko) for the newer kernel (DONE by default)
4) swap the xorg.conf file based on which kernel I boot into (easy to do)

There's a few steps I'm missing though, mainly how to get the actual nouveau drivers to work with the kernel. I edited my xorg.conf to use "nouveau" as drivers, but when I boot it goes into a black screen and doesn't work (not even into tty, just a black screen with a blinking cursor). I supposedly "installed" the nouveau drivers with "sudo apt-get install xserver-xorg-video-nouveau", I also edited the file in /etc/modprobe.d/ to remove the blacklist from the nouveau drivers (created by the nvidia proprietary drivers).

Any tips? Am I missing something? Obviously I'm not asking how to flip between the two drivers, that I will figure out myself, I just want to get nouveau to work on this kernel even though I have the nVidia drivers installed (for another kernel!).

Thanks for the help.