questions about implementing software dri driver

[Sean D'E. <se...@de...>]

Hi, I have been playing with mesa a lot recently.

I wanted to try the miniglx dri support that is in Mesa, I figured I could
use fb_dri.so for software rendering.  The only problem is it still needs 
to open a drm device (for locking), I don't have a supported card. So I hacked
together a kernel module that attaches to PCI:0:0:0 and provides 
/proc/dri/0

I had to modify fb_dri.c a bit to make it work, I am using Mesa 6.5, and
I think the last update for this file was 6.3.

My current module works, I am able to run opengl programs, only 32bit color
works correctly.

The problem is, when I try to unload the module I get:

Unable to handle kernel NULL pointer dereference at 0000000000000000 RIP:
<ffffffff88048d22>{:drm:drm_lastclose+210}
PGD 38969067 PUD 39d8c067 PMD 0
Oops: 0000 [7]
CPU 0

followed by a register dump.  I think this is because I am doing things
I am not supposed to do.

I really would like a way to provide the character devices and proc
interface without doing any pci calls, but I am not sure what the best
way to do all of this is.

I think having a dri kernel module that is meant to work with fb_dri.so
would be very useful for testing, and for systems without drivers.

Thanks,
Sean D'Epagnier