[RFC] Remove AGP support from Radeon/Nouveau/TTM

[Alex Deucher]

On Mon, May 11, 2020 at 4:41 PM John Paul Adrian Glaubitz
<glaubitz at physik.fu-berlin.de> wrote:
>
> On 5/11/20 10:05 PM, Alex Deucher wrote:
> >>> For Nouveau I'm not 100% sure, but from the code it of hand looks like we can do it similar to Radeon.
> >>>
> >>> Please comment what you think about this.
> >>
> >> I would be against such a move as AGP graphics is still used by people running the powerpc
> >> and ppc64 Debian ports on their vintage hardware [1].
> >>
> >> I have also CC'ed the debian-powerpc mailing list so that other users can voice their
> >> opinion.
> >
> > Note there is no loss of functionality here, at least on radeon
> > hardware.  It just comes down to which MMU gets used for access to
> > system memory, the AGP MMU on the chipset or the MMU built into the
> > GPU.  On powerpc hardware, AGP has been particularly unstable, and
> > IIRC, AGP has been disabled by default on radeon on powerpc for a
> > while.
> Do you have a code reference at hand for this bit of information (AGP
> being disabled on Macs)?

It was disabled 2 years ago:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=037d1a66ae640ca2723f47c0115ffa9e603699b3

Alex

>
> Thanks,
> Adrian
>
> --
>  .''`.  John Paul Adrian Glaubitz
> : :' :  Debian Developer - glaubitz at debian.org
> `. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
>   `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913