Troubleshooting Nouveau Drivers

Disable vga16fb

vga16fb is a driver which provides a simple framebuffer that can be used by applications to draw to the screen. Unfortunately, it can load in parallel with nouveau (or other kernel modesetting drivers), and if anything tries to use the framebuffer provided by vga16fb it will alter the state of the video card without the nouveau driver being aware of the change. This manifests in various ways, from corrupted graphics, to broken VTs, to just getting a blank screen on boot.

During boot hold down the shift key to get to the grub menu. Press the 'e' key to edit the boot command, and go down to the "kernel" line. Add "blacklist=vga16fb" after "quiet splash", then press Ctrl+x to boot. vga16fb will be disabled for this boot.

To permanently disable vga16fb you can add blacklist vga16fb to the end of /etc/modprobe.d/blacklist-framebuffer.conf, and run sudo update-initramfs -u.

Disable acceleration

Sometimes it can be useful to see if disabling acceleration improves things - particularly where there are rendering bugs.

During boot hold down the shift key to get to the grub menu. Press the 'e' key to edit the boot command, and go down to the "kernel" line. Add "nouveau.noaccel=1" after "quiet splash", then press Ctrl+x to boot. Acceleration will be disabled for just this boot. The GUI is likely to be slow with acceleration disabled!

If you want to disable acceleration permanently you can run the following commands:

echo options nouveau noaccel=1 | sudo tee -a /etc/modprobe.d/nouveau-kms.conf
sudo update-initramfs -u

Disabling nouveau

Sometimes it can be useful to disable nouveau to see if the computer boots correctly without it.

During boot hold down the shift key to get to the grub menu. Press the 'e' key to edit the boot command, and go down to the "kernel" line. Add "nouveau.modeset=0" after "quiet splash", then press Ctrl+x to boot. Nouveau will be disabled for this boot.

If you want to disable nouveau in this way permanently you can run the following commands:

echo options nouveau modeset=0 | sudo tee -a /etc/modprobe.d/nouveau-kms.conf
sudo update-initramfs -u

Reverting to the -nv driver

Disabling kernel mode setting will usually revert to the VESA driver which is slow, does not support many features like dual-head and may get set a poor resolution. You may be able to get a better experience with the -nv driver. To enable the nv driver, create or edit the /etc/X11/xorg.conf file to have the contents:

Section "Device"
        Identifier    "nvidia graphics card"
        Driver        "nv"
EndSection

Testing bugs against upstream Nouveau

If you've encountered a bug in the nouveau packages and want to invest some effort to help get it fixed, after you have reported it with ubuntu-bug you can test against a newer version of Nouveau in the xorg-edgers/nouveau PPA.

Warning: these packages are unsupported. They may have problems, including being unable to get to a GUI. If you are not comfortable debugging video driver problems, please do not proceed.

First, enable the xorg-edgers/nouveau PPA and upgrade the nouveau packages by running

sudo add-apt-repository ppa:xorg-edgers/nouveau
sudo apt-get update
sudo apt-get dist-upgrade

You will need to reboot to apply these changes properly.

Now, see if you can reproduce your bug.

• If the bug is still present in the updated packages, please make a note of the bug number of your bug report and run apport-collect YOUR_BUG_NUMBER.

• If the bug has been fixed in the updated packages, please note this on your bug also so we can pull the fix into the Ubuntu packages.

Reverting to official packages

To revert to the official Ubuntu packages you can use the ppa-purge tool. To go back to the Ubuntu packages, run

sudo apt-get install ppa-purge
sudo ppa-purge ppa:xorg-edgers/nouveau

and reboot.