Xorg 7.0 RC0 on powerbook yields garbled text

[Greg Roth]

> 1. DDX - 2d driver; handles card setup, mode/output control, and Xv. 
> radeon_drv.(s)o for all radeon chips; resides in
> /usr/X11R6/lib/modules/drivers
> Driver is maintained in xorg cvs
> 
> 2. DRI library - 3d driver; sets up the 3d engine and build the 3d
> pipeline.  provides an openGL interface to the 3d engine.  r300_dri.so
> for r3/4xx chips, r200_dri.so for r2xx chips and radeon_dri.so for
> r100 chips; reside in /usr/X11R6/lib/modules/dri
> Driver is maintained in mesa cvs
> 
> 3. DRM - a kernel module that provides secure multiplexed access to
> the card for  use by the 3d and optionally 2d engines for command
> submission, DMA, interrupt handling, etc. radeon.(k)o for all radeon
> chips.  resides in your kernel module tree.
> Driver is maintained in dri cvs
> 

I see. I'd read this distinction before, but never with specific examples. 
It's the DDX part I was hitherto unclear on. Thanks for the elucidation. 

If I understand then, prior to the r300 driver, I would have been using 
the radeon DDX driver, which is what the 'Driver "radeon"' line is about,
and all the "DRI" lines in xorg.conf are to trigger the loading of the 
appropriate DRI library. Which library is to be loaded isn't explicitly 
specified anywhere so it must figure that out internally. Is that right?

Am I to understand then that before the r300 library, my DRI lines where
effectively ignored because the internal mechanism whereby it determines
which DRI library to load found no DRI library matching my hardware?

Then the DRM is the same for any radeon card?

I do appreciate your enlightening me on this matter. It's something about 
which I've been curious for some time.

Greg