Notes for porting DRI to Solaris

Official home page for DRI is at http://dri.sourceforge.net/
A conceptual discussion of DRI is at http://www.precisioninsight.com/dr/drill.html

Trouble is, you need a very non-portable driver written specifically for your OS, to have this work. Linux has one. BSD has one. Solaris does not.

I may never have the time, or patience, to write a DRI kernel module for solaris. But here are some public notes for anyone thinking about doing the project. These are things I'm writing down as I'm looking at the code. I do not have any special "inside" knowlege - I did not work on either of the two working drivers

Top-level directory

All filenames and directories referenced on this page assume that you are sitting in the directory

xc/programs/Xserver/hw/xfree86/os-support/

You get this directory by extracting X410src-1.tgz from xfree86.org (or whatever filename is the current "archive 1 of 3" when you read this)

Interesting files and directories

xf86drm.h

This file is what the user-level library looks at. Eventually, you must use everything in this file.

linux/drm/xf86drm.c

This file is actually the USER-SIDE library. You must implement the corresponding driver side to everything in this file. There are card-specific extras in the same directory that also must eventually be made happy. Specific cards may require specific extra ioctl support at driver level.

bsd/drm/

This directory is a cheat. It SOFT-LINKS all the files in linux/drm/, and compiles them for bsd.

linux/drm/kernel/

Finally, the actual kernel driver routines. You should really look at the BSD drivers more, but there are critical include files in this directory. Most importantly, "drm.h"

bsd/drm/kernel/ (and subdirectories)

Here is the actual BSD driver source, fairly nicely organized. There are two gotchas:

1. It softlinks all the .h files from the linux kernel dir, as noted above
2. There are no .c files here. The generic non-card-specific code is in the drm subdirectory. The generic code currently comprises 5000 lines of C code.
   500 lines of that is non-needed "/proc" support, and another 500 lines is the BSD/xfree license preamble.

Functionality categories

• Allowing memory mapping of device memory
• Allowing mapping of registers (not really treated separately from device memory, I think)
• Handling DMA mapping and use (which means handling interrupts as well). It is claimed that if memory mapping is used, DMA is not required.
• AGP bus manipulation, if required

Dec 26, 2001: I have just released a prototype for a /dev/agpgart driver. See my AGP driver section, on the main driver page.

There are other misc. little details, like access control to the device, but I think for the first round, those should be unneccessary.