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Revision as of 18:55, 1 September 2013 by Lahwaacz (Talk | contribs) (Hardware Specific: covered generally in Via#Troubleshooting, no need to duplicate for specific hardware)

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Different Unichrome family display drivers

The VIA proprietary drivers

These are considered unstable and insecure. They are however the only way to get any form of 3D acceleration or even reliable modesetting on certain chipsets, and can be installed using one of the following packages from the AUR:

The OpenChrome driver

The most advanced and developed driver for Unichromes. Supports CLE266, KM400/KN400/KM400A/P4M800, CN400/PM800/PN800/PM880, K8M800, CN700/VM800/P4M800Pro, CX700, P4M890, K8M890 and P4M900/VN896 chipsets. Accelerates 2D, 3D, Xvideo and mpeg2 decoding using XvMC. This driver is the only way to go if you want to be on the bleeding edge.

To get the OpenChrome driver, install the xf86-video-openchrome package.

The xorg.conf driver name is openchrome.


To enable any of the following options to fix issues, first create a new file 10-openchrome.conf in /etc/X11/xorg.conf.d/:

Section "Device"
    Identifier "My Device Name"
    Driver "openchrome"

If your X Server shows artifacts and fails to redraw some windows, try disabling the EnableAGPDMA option:

Option     "EnableAGPDMA"               "false"

If your machine freeze at startup (GDM) or after login (slim), try adding the XAA option XaaNoImageWriteRect. Note that this only applies if you are using the XAA acceleration method (configured by the AccelMethod option). Since 0.2.906, the default acceleration method is EXA.

Option "XaaNoImageWriteRect"

If you experience significant CPU usage and low UI framerate, try adding:

Option "AccelMethod" "XAA"
Black screen when booting from LiveCD

If you experience a black screen when booting from Live-CD, add modprobe.blacklist=viafb on the kernel command line.

Note: The nomodeset option will probably not work here.

After installing the system you will need to blacklist the viafb module.

Unichrome and OpenGL

OpenGL support for Via's graphic chipsets is seriously outdated. At the moment you will not be able to run more fancy applications, games or compositing desktops like Compiz Fusion that rely on OpenGL as a backend, because the more recent OpenGL extensions are not yet supported in Unichrome 3D driver. You will be able to run simple OpenGL-applications though. The 3D driver for Unichrome is provided by the the DRI project.

Install unichrome-dri, mesa-libgl and mesa packages to get OpenGL to work.

DPMS problems

If you experience problems with DPMS not turning off laptop's backlight, try adding:

Option "VBEModes" "true"

to the device section of xorg.conf.

Hangup on exit

If your computer crashes when closing X, you may try not using vesa driver for kernel console. Just delete the vga stuff from kernel line on grub or append line on lilo.

See also