Make.conf/VIDEO CARDS/NVIDIA and Nouveau Driver Switching

This page describes how to switch between nvidia and nouveau graphics drivers from the boot menu with the same kernel.

Background

The use of libglvnd was introduced with Funtoo Release 1.4. libglvnd provides for the automatic detection and configuration of the graphics driver during boot. When more than one driver is available for the same card, the configuration depends on the driver detected. Previous to Release 1.4, the proper configuration was provided by 'eselect opengl'. The selection between the nvidia and nouveau driver for a Nvidia graphics card is such a case.

Switching drivers from the boot menu requires blacklisting of all graphics kernel modules (including drm) and configuring the graphics from an init daemon before Xorg is started. This will not work, for instance, if the kernel has been configured for the plymouth splash screen. The prebuilt debian-sources-lts kernel provided in the Funtoo stage3 base system is consistent with the switching prodcedure.

System Profile

Check your system profile with ego. Both the gfxcard-nouveau mix-in and either the gfxcard-nvidia orgfxcard-nvidia-legacy mix-in need to be in your profile and installed. Check the information here and here.

boot-update

The most important change: edit /etc/boot.conf:

/etc/boot.conf

boot {
	generate grub
	default "Funtoo Linux [nvidia]" 
	# or
	# default "Funtoo Linux [nouveau]"
	timeout 3 
}

color {
	normal cyan/blue
	highlight blue/cyan
}

display {
	#gfxmode 1280x800
	#font unifont.pf2
}

"Funtoo Linux [nvidia]" {
	kernel vmlinuz[-v]
	params += ro console=tty1 quiet <other standard boot options>
	params += nouveau.blacklist=true vga=791 # nouveau.blacklist=true is important
	# or
	# params += nouveau.blacklist=true video=uvesafb:1440x900-8,mtrr:2
}

"Funtoo Linux [nouveau]" {
	kernel vmlinuz[-v]
	params += ro console=tty1 quiet <other standard boot options>
	params += nvidia.blacklist=true # nvidia.blacklist=true is important
}

Next, run boot-update.

After boot-update has been run, you should have something like:

root # grep menuentry /boot/grub/grub.cfg | wc -l
2
root # grep menuentry /boot/grub/grub.cfg
menuentry "Funtoo Linux [nouveau] - vmlinuz-2.6.32.71_p14-rh" {
menuentry "Funtoo Linux [nvidia] - vmlinuz-2.6.32.71_p14-rh" {

Next, we will blacklist all the graphics kernel modules:

/etc/modprobe.d/blacklist

blacklist drm
blacklist nouveau
blacklist nvidia
blacklist nvidia_modeset
blacklist nvidia_drm

xcfgmaker deamon

A Section "Device" must be provided for each driver. The most basic form is:

Section "Device"
    Identifier     
    Driver         "nvidia" #or "nouveau"
    VendorName     
    BoardName      
    Option    
EndSection

root # mkdir /etc/X11/video/;
root # cd /etc/X11/video/;
root # nano 10-monitor.conf.nouveau # make default config for nouveau. or copy existing config… 
root # nano 10-monitor.conf.nvidia # also for nvidia

Then create a new daemon. Edit the file /etc/init.d/xcfgmaker:

!/sbin/openrc-run

by http://wiki.sabayon.org/index.php?title=HOWTO:_Create_a_boot_option_for_easy_dual_to_single_display_switching
To be placed in /etc/init.d/
Run Command: rc-update add xcfgmaker boot

depend() {

  need localmount
  before xdm-setup
  before xdm
  before alsasound

}

start() {

  cmdline_display_mode_exist=$(cat /proc/cmdline | grep -e "nouveau.blacklist=" -e "nvidia.blacklist=")
  display_mode_nvidia_exist=$(ls /etc/X11/video/ | grep "10-monitor.conf.nvidia")
  display_mode_nouveau_exist=$(ls /etc/X11/video/ | grep "10-monitor.conf.nouveau")
  cmdline_display_mode=$(cat /proc/cmdline | awk -Fnvidia.blacklist= '{print $2}' | awk '{print $1}')
  if [ -n "$cmdline_display_mode_exist" ]; then
     if [ -n "$display_mode_nvidia_exist" ] && [ -n "$display_mode_nouveau_exist" ]; then
           #Choose the xorg file to be copied over
           if [ "$cmdline_display_mode" == "true" ]; then
              ebegin "Configuring X display with nouveau"
              cp /etc/X11/video/10-monitor.conf.nouveau /etc/X11/xorg.conf.d/10-monitor.conf

eselect opengl set xorg-x11 >/dev/null 2>&1;

              /sbin/modprobe drm
              /sbin/modprobe nouveau;
           else
              ebegin "Configuring X display with nvidia"
              cp /etc/X11/video/10-monitor.conf.nvidia /etc/X11/xorg.conf.d/10-monitor.conf

eselect opengl set nvidia >/dev/null 2>&1;

              /sbin/modprobe nvidia-drm;
          fi
        sleep 5
        eend 0
     else
        ebegin "Xorg file missing. Exitting"
        eend 0
     fi
  fi

}

Do not forget:

root # chmod +x /etc/init.d/xcfgmaker
root # rc-update add xcfgmaker boot

Additional Resources