Nouveau & nvidia-drivers switching

This article describes how to switch between NVIDIA's binary driver and the open source nouveau driver.

Switching using two kernels[edit | edit source]

General setup  --->
    (-mykernel-nvidia) Local version - append to kernel release

Device Drivers  --->
    Graphics support  --->
        <*> Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)
        <M> Nouveau (NVIDIA) cards

VIDEO_CARDS="nvidia nouveau"

#!/bin/bash

depend() {
	need localmount
	before xdm
}

if [[ $(uname -r) == *-nvidia ]] ; then
	modprobe -q nvidia
cat > /etc/X11/xorg.conf.d/01-nvidia.conf << EOF
Section "Device"
  Identifier   "Device0"
  Driver       "nvidia"
  Option       "NoLogo" "True"
EndSection
EOF
else
	modprobe -q nouveau
	if [ -f /etc/X11/xorg.conf.d/01-nvidia.conf ] ; then
		rm /etc/X11/xorg.conf.d/01-nvidia.conf
	fi
fi

Switching using a single kernel and hprofile[edit | edit source]

Another method is switching between two profiles with hprofile, using a single kernel: /etc/init.d/hprofile has to be modified adding a few lines for VGA switching. Warning: hprofile shall be added in boot runlevel.

Switching using a single kernel and systemd[edit | edit source]

If you have your system configured to use systemd, you can control setting nvidia and nouveau by using the functionality provided by the kernel command line.

Within the grub.cfg file you need to duplicate the desired menu item and then edit the two versions to specify which modules with be blacklisted, and to pass an environment variable to systemd. If you previously blacklisted nvidia or nouveau modules in /etc/modprobe.d then you need to remove them since that will now be controlled directly from the kernel command line.

menuentry 'Gentoo Linux' {
        root=hd0,1
        linux /boot/bzImage root=PARTUUID=11111111-2222-3333-4444-555555555555 init=/usr/lib/systemd/systemd console=tty1
}

menuentry 'Gentoo Linux - Nouveau' {
        root=hd0,1
        linux /boot/bzImage root=PARTUUID=11111111-2222-3333-4444-555555555555 init=/usr/lib/systemd/systemd console=tty1 modprobe.blacklist=nvidia systemd.setenv=GPUMOD=nouveau
}

menuentry 'Gentoo Linux - Nvidia' {
        root=hd0,1
        linux /boot/bzImage root=PARTUUID=11111111-2222-3333-4444-555555555555 init=/usr/lib/systemd/systemd console=tty1 modprobe.blacklist=nouveau systemd.setenv=GPUMOD=nvidia
}

Next we are going to use a small script similar to the one shown in the "Switching using two kernels" section. It is very similar, but slightly modified. For the sake on continuity we will place it in the same location. The main difference is that is does not use the kernel's name to determine which profile to use, but rather it uses a variable set in the environment by systemd from the kernel command line.

#!/bin/bash

if [[ "$GPUMOD" == "nvidia" ]] ; then
cat > /etc/X11/xorg.conf.d/01-nv.conf << EOF
Section "Device"
  Identifier   "Device0"
  Driver       "nvidia"
  Option       "NoLogo" "True"
EndSection
EOF
else
cat > /etc/X11/xorg.conf.d/01-nv.conf << EOF
Section "Device"
  Identifier   "Device0"
  Driver       "nouveau"
EndSection
EOF
fi

As mentioned in the previous section, don't forget to set the executable bit.

To have this script get called during the systemd init process, you can create a service file for it, but it's just as effective to integrate it into the currently existing xdm, gdm, sddm or other(?) display manager service file. You don't want to edit the service file directly, since that will get overwritten the next time that package is merged that the service file belongs to. Instead you create an override for the service file, placed in the /etc/systemd/system/service-name.d/ directory.

So for example if you use sddm.service you would create the directory /etc/systemd/system/sddm.service.d and place a file in it with a .conf file extension. Add a [Service] section that has an entry for ExecStartPre to call nvidia.start before sddm itself is started.

[Service]
ExecStartPre=/etc/local.d/nvidia.start

Switching using a single kernel in an Optimus system without reboot[edit | edit source]

In an Optimus system, the graphics is handled by the Intel integrated card, while the user can choose to run specific programs with the NVidia dedicated card. This means that the modules handling the NVidia card can be safely force-unloaded and reloaded without reboot.

Follow the steps in the NVIDIA/Bumblebee page, and then add the nouveau flag to VIDEO_CARDS:

VIDEO_CARDS="intel i965 nvidia nouveau"

Then update the system using the following command so the changes take effect:

Also, Bumblebee should NOT start on boot:

Then, follow the steps at https://wiki.freedesktop.org/nouveau/Optimus/. In short, list the available providers (which are the video cards):

The exact output will differ for each system, but the important parameter is name. Then, define which card should be used for offloading:

This will set Nouveau for offloading the Intel card. Replace the names nouveau and Intel with the names shown before.

After reboot, your system should be using Nouveau to handle the cards. The following script can be used to switch between nouveau and nvidia-drivers:

#!/bin/sh

Driver="$1"

/etc/init.d/bumblebee stop
rmmod -v -f nouveau
sleep 1

if [ "${Driver,,}" == nouveau ]; then
    modprobe -q nouveau

elif [ "${Driver,,}" == nvidia ]; then
    /etc/init.d/bumblebee start;

else
    echo "Choose a graphics driver [nouveau or nvidia]."
fi

Make it executable:

Testing: