3D hardware acceleration requires a DRI kernel module that's specific to your graphics hardware.
The DRI kernel module version must exactly match your running kernel version. Since there are so many versions of the kernel, it's difficult to provide precompiled kernel modules.
While the Linux source tree includes the DRI kernel module sources, the latest DRI kernel sources will be found in the DRI source tree.
See the DRI Compilation Guide for information on compiling the DRI kernel modules.
XFree86 4.0.1 added automatic kernel module loading to the X server.
On Linux, the X server uses modprobe to load kernel modules.
In Linux 2.4.x the DRM kernel modules should be kept in
/lib/modules/2.4.x/kernel/driver/char/drm/ for automatic
loading to work.
Optionally, DRM kernel modules can be loaded manually with insmod prior to starting the X server.
You can verify that the kernel module was installed with lsmod, checking the X server startup log, and checking that /proc/dri/0 exists.