device drm with PCIe?

[Eric Anholt]

On Fri, 2005-12-16 at 12:30 -0500, Jung-uk Kim wrote:
> On Thursday 15 December 2005 07:36 am, O. Hartmann wrote:
> > Normally 'device drm' is only useable in conjunction with 'device
> > agp'. A lot of amd64 based boxes now use PEG slots for their
> > graphics accelerators. Is it possible to utilize 'drm' with PCIe
> > devices?
> 
> Yes.  It should work, at least in theory. ;-)
> 
> > Does device agp has any effect on PCIe graphics accelerators?
> 
> No.  You don't need it for PCI-Express controller.

Now, this is stuff I don't 100% understand, but what I've figured out so
far is that for graphics, you're going to need a GART somewhere.  For
their PCIE cards, ATI deals with this by doing essentially the old
PCIGART method but tweaked, in lieu of AGP.  Intel's PCIE graphics, on
the other hand, has a GART on their chips that is basically the same
thing as their previous AGP GARTs, at least in terms of programming.  So
we expose their gart through the agp device still, even though the
chipset may be PCIE.

-- 
Eric Anholt                                     eta at lclark.edu
http://people.freebsd.org/~anholt/              anholt at FreeBSD.org
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