Messages in this thread | | | Date | Wed, 20 Aug 2008 16:27:22 +0200 | From | Rene Herman <> | Subject | Re: AGP and PAT (induced?) problem (on AMD family 6) |
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On 20-08-08 12:50, Rene Herman wrote:
> On 20-08-08 12:04, Ingo Molnar wrote: > >> * Venki Pallipadi <venkatesh.pallipadi@intel.com> wrote: >> >>>> I'd really like a reply from the AGP or PAT side right about now. >>> Hmm. Looks like there are more than 16000 entries in the PAT list! >> >> hm, btw., why is that? > > Because 64M of AGP memory divided by 4K pages is 16K. That is, the > underlying problem seems to be AGP drivers using order 0 allocations. > I'm looking. > > Do note also that this means that Venki's change would not constitite a > correct/final fix. Sure, caching the last entry speeds up traversing a > 16K entry list but the issue is that there shouldn't be a 16K entry > list. Through AGP, or maybe even by coalescing entries in the PAT list > if that's at all possible (I guess it's not really). > > Even if such a more fundamental fix isn't (easily) available, the PAT > code already comments that the list, which is sorted by ->start value, > is expected to be short, and should be turned into an rbtree if it isn't > which might be slightly less of a bandaid. > > Dave Airlie (as the MAINTAINERS entry) can't be arsed to answer email it > seems so I've added Dave Jones for a possible comment from the AGP side. > If I'm reading this right upto now, still many AGP driver (among which > my amd-k7-agp) are affected.
This was based on a wrong reading; I was looking at the GATT allocation.
I'm giving up looking until someone can tell me whether or not those 16K entries are expected though. I have just one AGP card in a PAT capable machine.
How many entries in /debug/x86/pat_memtype_list are there on other AGP systems with Option "AGPSize" "64" in their xorg.conf:"Device" section (and their AGP aperture set to 64M or bigger in the BIOS)?
Rene.
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