[Dri-devel] Re: __MUST_HAVE_AGP.... anything ok now!

[Guido Landra]

Thank you everybody for quick and very good answers and hints!!!
:)

 -- I patched kernel 2.4.20-8 (RedHat 9,  XFree86 4.3.0) by diff file downloaded from

http://www.codemonkey.org.uk/agp/nvidia.shtml

Now agpgart.o module can be loaded and is correctly used by dri drivers.
I am currently running some test applications on it.

-- About PCI/AGP issue, I  understood that radeon driver can send commands to card in two ways:
 1) MMIO, available on both AGP and PCI.
 2) system memory block seen by the GPU (GART), available on all AGP cards and on some PCI cards.
The first mode is supported on all platforms (x86, alpha, etc.), an all cards (7xxx, 8xxx, ...), on all buses (PCI, AGP) but is able only to accelerate 2D.
The second mode is mandatory for accelerating 3D and can optionally accelerate 2D: it is supported on all AGP cards and on radeon PCI-based cards (but at driver-level only on alpha platform it is implemented).

My original idea was to enable DRI without using agpgart.o (because I was having problems with nforce north bridge not supported).
It is theoretically possible using PCI GART but it is currently not implemented on x86 based systems, only on alpha (I have a pc....).

Is this correct?

Guido

Mike A. Harris wrote:

On Wed, 11 Jun 2003, [iso-8859-15] José Fonseca wrote:

  

Are there some radeon AGP cards able to work without agpgart?
      

Which drivers are you using?  PCI support in Radeon was busted some time
ago, which meant that AGP had to be present.
    

To be clearer to the original person, PCI DRI support didn't work
except on Alpha architecture.  Radeon hardware worked fine in 2D
only with DRI disabled though, on both AGP and PCI cards.

  

I have an nvidia NFORCE1-based motherboard.
Agpgart module does not support my north bridge: does this mean that I 
can't accelerate any AGP card (radeon 7200 for example)?
      

That's a difficult question. I don't know whether the Radeon hardware
allows to be run in PCI mode.
    

All Radeon hardware should work fine in PCI mode.  Wether or not 
XFree86/DRI drivers are up to scratch on a given XFree86 release 
or not is another question though.  It is much better nowadays 
than in the past though.

  

The issue is that the Radeon driver for PCI cards relies on the
existence of a PCI-GART (it does the same as the AGP GART, but
in the PCI bus) which I don't know if it's present on AGP cards.
    

It is, and should work on AGP cards just like a PCI card, with 
"ForcePCIMode".