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Date: Wed, 13 Apr 2011 23:10:03 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Dave Airlie <airlied@redhat.com>
CC: Yinghai Lu <yinghai@kernel.org>,
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Subject: Re: Linux 2.6.39-rc3
References: <BANLkTimNvX=U6qy2FgvDpWE6HY7cehWvyQ@mail.gmail.com>	 <20110412090207.GE19819@8bytes.org>	 <BANLkTimSgAmT5a1s0ciBr2jsE-Nu7n4buQ@mail.gmail.com>	 <20110412184433.GF19819@8bytes.org> <20110413064609.GA18777@elte.hu>	 <20110413172147.GI19819@8bytes.org> <4DA5F62F.3030504@kernel.org>	 <4DA654D6.2060103@zytor.com> <1302746853.4842.20.camel@clockmaker-el6>
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On 04/13/2011 07:07 PM, Dave Airlie wrote:
>>
>> Okay, staring at this, it definitely seems toxic to overlay the GART
>> over memory areas reserved by the BIOS.  If I were to guess, I would say
>> that the problem here seems to be that the kernel thinks it is
>> overlaying 64 MiB of memory, but the actual GART is in fact 512 MiB in
>> size -- 131072 CPU pages -- which now overlaps the BIOS reserved areas.
>>
>> Alex D., could you comment on the "num cpu pages" bit?
> 
> These are not CPU addresses. I think we've stated that already. Not the
> droids.
> 
> the num cpu pages is how many CPU pages would be needed to fill the GPU
> GTT, for those crazy cases where CPU pagesize != GPU pagesize.
> 

OK, well, something is still weird.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.