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



Am 11.05.20 um 22:46 schrieb Alex Deucher:
On Mon, May 11, 2020 at 4:41 PM John Paul Adrian Glaubitz
<glaubitz@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

To be honest from the hacks we have in there to get this working I'm even surprised that this ever worked at all on PowerPC.

Going to extend this patch for now and add a config option to not compile in AGP GART support for TTM any more instead of removing it.

Christian.


Alex

Thanks,
Adrian

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  .''`.  John Paul Adrian Glaubitz
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