From: James Simmons <jsimmons@edgeglobal.com>
  To  : ggi-develop@eskimo.com
  Date: Fri, 23 Apr 1999 12:39:14 -0400 (EDT)

Re: 2 questions

On Fri, 23 Apr 1999 becka@rz.uni-duesseldorf.de wrote:

> > My plan was mainly to run 1 MGA Millenium and one card with something
> > else. But I can also get a hold of another Millenium. Can I not run even
> > one of them accelerated? (I don't know a great deal about this). 
> 
> IF the Millenium 1 works with out kgicon driver, it will be accelerated.

Ha? If you use the kgicon driver you can get the acceleration by ioctl
calls. If you use the default linux kernel driver matroxfb than you will
have no default acceleration.
 
> > And how difficult is it to make matroxfb accelerater?
> 
> Coding wise it wouldn't. But the kernel people dislike kernel mode accel.

Their is a trick to use the default kernel drivers for acceleration. Its
just not safe to do it with some cards. If you look in fb_fix_screeninfo
you will see mmio_start and mmio_len. You can use that info to mmap all
the matrox registers. For my Millenium card it maps 16K of registers to
userland. I remember Marcus talking about writing some code for fbdev to
support this safely. No mind you this is not safe. You must yourself
regulate fb access and the accelerator engine access. If you try to use
the accels and framebuffer at the same time you can lock your system.