Re: [RFC PATCH] Utilize the PCI API in the AGP framework.

From: Konrad Rzeszutek Wilk
Date: Mon Dec 06 2010 - 21:12:55 EST


> Okay reading that I'm not sure you've started at the right end.

I actually have all of those patches ready but figured I would start
from the AGP side..
>
> I just read 601341, and it concerns nouveau, which shouldn't on the hw
> described be touching AGP at all. Its a PCIE machine, so the DRM/TTM
> code won't use any of the AGP paths.

I think most of them do touch PCIe cards. I swore that there were
some AGP users out there, maybe they aren't on those bugs - let me search
my mail archive. Maybe it just me who still uses AGP...
>
> Now if we have fixes for TTM/nouveau/radeon that make it work under Xen
> then that is a whole different story, however these patches are not
> those.

Nope. I just posted them: https://lkml.org/lkml/2010/12/6/516

>
> I'd suggest you reverse the priority, of the comment
>
> a) Fix the GART/AGP backend (so drivers/char/agp/*.c) so they use the
> PCI API.
> Only the i915 and higher are using the PCI API and I've some of the older
> boxes with i860 so can actually test it.
> b) Fix the TTM to use the DMA API.
> c) Lastly, get rid of _PAGE_IOMAP so we don't have to depend on radeon/nouveau/etc
> to set the proper _PAGE_IOMAP on the PFNs/BARs..
>
> to do c, then b, and finally figure out if anyone cares about a, unless there is a major dependency in the code that requires this ordering.

There is a patch for c) that is nice and simple:
http://git.kernel.org/?p=linux/kernel/git/konrad/xen.git;a=commit;h=f5d630621f6616a8a14438c047332742e77c0739

but we are working on making that obsolete by .. well I can go in details
but it still is just on pieces of paper.
>
> Dave.
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