thanks for the quick response!
obviously at the moment i'm running X without dri, but i tried another attempt with dri enabled in xorg.conf, and here is what happened:
agpgart and tdfx (EDIT plus tdfx_drv now

) are both loaded modules, but lsmod says that they are both unused. when compiling the kernel i tried to get drm as a module so as to follow instructions completely, but it would only compile built-in.
<<edit>> i discovered that you have to compile the drm kernel modules yourself (duh!), so i have now done that and X starts well. it also says in the Xorg.0.log that direct rendering is enabled. however, when i run glxinfo it still says that it is disabled, and a test run of graal (which indicates whether you have direct rendering enabled or not on startup) gives the same output. the 'vendor' string of the glxinfo output still gives Mesa etc etc. help, please!