After writing earlier this week about VIA quietly having a Gallium3D driver unknown to most of the Linux desktop community, I was digging a bit deeper to see if there's any other hidden mysteries for VIA on Linux. To not much surprise, the OpenChrome open-source VIA graphics driver is far from being feature-complete by any means.
For those unfortunate souls stuck with VIA x86 hardware, the FreeDesktop.org OpenChrome support matrix was coincidentally updated this week. This Wiki page reflects the state of OpenChrome for both its user-space mode-setting and kernel mode-setting drivers.
When it comes to OpenChrome UMS with VGA and LVDS outputs, at least there is support from the old CLE266 through the new VX900. That's all in good standing. Where the pain begins is when it comes to HDMI and DVI support, regardless of whether there's an internal or external TMDS transmitter, DisplayPort is not hooked up, there is no display hot-plug support, and dual screen also doesn't work. Aside from UMS mode-setting, there is EXA 2D acceleration, X-Video, XvMC support for some older chipsets, and no 3D support.
The OpenChrome KMS support done by James Simmons comes down to working VGA, LVDS working with integrated transmitter, work-in-progress HDMI and DVI support, no DisplayPort, no TV output support, no dual-screen support, hot-plug support for some VIA chipsets, and there is no EXA/X-Video/XvMC/3D along the KMS driver's code-paths.