The old Compaq AVGA chipset is supported by the XF86_SVGA server with the compaq driver. The status of this support is unknown because we don't have any recent test reports, and this driver has no maintainer.
Support (accelerated) for the DEC 21030 TGA 8 plane, 24 plane and 24 plane 3D chips (on Alpha platforms) is provided by the XF86_TGA server.
No support exists for the Compaq AVGA (its driver hasn't been ported).
Support (accelerated) for the DEC 21030 TGA 8 plane, 24 plane and 24 plane 3D chips (only tested on Alpha platforms) is provided by the "tga" driver.
No Compaq AVGA chips are supported in 4.2.0. DEC TGA support is equivalent in both 3.3.6 and 4.2.0.