[PATCH] agp: use scratch page on memory remove and at GATT creation V4

[Matt Turner]

On Thu, Apr 22, 2010 at 6:30 AM, Jerome Glisse <jglisse at redhat.com> wrote:
> On Thu, Apr 22, 2010 at 11:27:11AM +0200, Daniel Vetter wrote:
>> On Tue, Apr 20, 2010 at 05:43:34PM +0200, Jerome Glisse wrote:
>> > Convert most AGP chipset to use scratch page as default entries.
>> > This help avoiding GPU querying 0 address and trigger computer
>> > fault. With KMS and memory manager we bind/unbind AGP memory
>> > constantly and it seems that some GPU are still doing AGP
>> > traffic even after GPU report being idle with the memory segment.
>> >
>> > Tested (radeon GPU KMS + Xorg + compiz + glxgears + quake3) on :
>> > - SIS 1039:0001 & 1039:0003
>> > - Intel 865 8086:2571
>> >
>> > Compile tested for other bridges
>> >
>> > V2 enable scratch page on uninorth
>> > V3 fix unbound check in uninorth insert memory (Michel Dänzer)
>> > V4 rebase on top of drm-next branch with the lastest intel AGP
>> >    changeset (stable should use version V3 of the patch)
>>
>> Nope, v3 still contains the bogus changes to the intel gtt driver (only
>> used by intel igds). In this patch, the intel parts look good.
>>
>> While looking add this I've found some more stuff to nit-pick over ;)
>> Instead of splattering needs_scratch_page = true all over the agp drivers,
>> why not do the changes in the agp core (and the few fixups required in the
>> drivers) and simply kill this variable? If using a scratch page is
>> required by upper layers (drm/radeon), then keeping around this "looks
>> optional, but is very much a core requirement" thing lingering around is
>> quite a call for trouble, IMHO.
>>
>> Yours, Daniel
>> --
>> Daniel Vetter
>> Mail: daniel at ffwll.ch
>> Mobile: +41 (0)79 365 57 48
>
> V4 is ok it apply on top of drm-next, and no i don't kill
> needs_scratch_page because i don't want to touch Alpha AGP
> code (i think it should die, i don't think alpha got AGP
> hw we care about or even support).
>
> Cheers,
> Jerome

(Working) AGP is only available on high-end systems [1].

I've been working on Alpha things for two years now, and I've talked
to only a single person with one of these systems, and he worked at HP
at the time. I'd certainly like to keep these supported, in the case
someone decides to donate one to me. :)

If you want to have any changes against Alpha AGP checked, Ivan
Kokshaysky is your guy.

Matt

[1] http://alphalinux.org/wiki/index.php/User:Mattst88/Alphas_with_AGP