VIA_Unichrome

1 About
2 Installing Gentoo
3 Kernel
4 Xorg configuration
5 Credits

About

This Howto is about installing a kernel and Xorg on a motherboard with a VIA Unichrome (Pro) graphics chip.

Some VIA chipsets support hardware MPEG2/MPEG4 decoding of videos, thus taking the load off the CPU. At the end of this howto you should be able to play a mpeg2 file with as little as 5% CPU usage. Multiple mpeg2 steams are not supported by the hardware, so you will only get hardware decoding for one video file.

Note: If you are using current xorg-x11 version 7, please look in the discussion tab above and in the new project that successed. And especially its Gentoo article.

Note: There is an ebuild in Portage for this driver: x11-drivers/xf86-video-openchrome.

Installing Gentoo

Set the following USE flag in order to use hardware MPEG2/MPEG4 decoding automatically in supportive packages.

Code: Kernel Configuration

USE="xvmc"

Actually mplayer needs both "xvmc" and "xv" in order to configure itself with xvmc support.

Kernel

I think we can assume that anyone wanting to get a Unichrome chipset working has a modern kernel version. Select the following options in the kernel config screen:

Code: Kernel Configuration

Device Drivers  --->
 Character devices  ---> 
  <*> /dev/agpgart (AGP Support)
   <*> VIA chipset support
  <*> Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)
   <*> Via unichrome video cards

Xorg configuration

Now install Xorg, the required tools for an openchrome installation and the openchrome driver itself using the following commands:

Code: Install Xorg

# Merge Xorg
emerge xorg-x11

# Emerge subversion
emerge subversion

# Install openchrome driver
mkdir /tmp/openchrome
cd /tmp/openchrome
svn co http://svn.openchrome.org/svn/trunk
cd trunk
./autogen.sh
./configure --prefix=/usr --enable-maintainer-mode
make
make install

On some laptop panels there appears to be problems with Xorg automatically detecting refresh rates which causes the driver to fail. In order to resolve this issue add the following (or something similar) to your xorg.conf file under the Monitor section.

File: xorg.conf

HorizSync    31.5 - 48.5
VertRefresh  40.0 - 70.0

Credits

Thanks to Ivor, Totte, Radagast, Rroet and all others who made these boards usable!
Thanks also to all who have anything to do with the Unichrome Project and the Openchrome Project.
Most knowledge gathering took place on EpiaWiki. (Dead link / domain broker)
Some other stuff can be found on Epia at Kalf.org. (Dead link)
Additional infos can be found at the Viaarena Linux Forum.

Finally, thanks to VIA for the hardware...

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