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From: ebiederm@xmission.com (Eric W. Biederman)
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Yinghai.Lu@Sun.COM, Muli Ben-Yehuda <muli@il.ibm.com>,
       Andi Kleen <ak@suse.de>, Andrew Morton <akpm@linux-foundation.org>,
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       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86-64: disable the GART before allocate aperture
References: <200706221219.16243.yinghai.lu@sun.com>
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	<20070622213327.69663288@the-village.bc.nu>
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Date: Fri, 22 Jun 2007 17:14:23 -0600
In-Reply-To: <20070623000405.15eb66f1@the-village.bc.nu> (Alan Cox's message
	of "Sat, 23 Jun 2007 00:04:05 +0100")
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Alan Cox <alan@lxorguk.ukuu.org.uk> writes:

> On Fri, 22 Jun 2007 15:57:08 -0700
> Yinghai Lu <Yinghai.Lu@Sun.COM> wrote:
>
>> Alan Cox wrote:
>> 
>> > Don't disable it, just don't touch it or any of its mappings. Leave it
>> > *alone*, and use swiotlb. That'll maximise the ability to recover stuff
>> > from the kexec kernel (since for one you may want to dump the gart when a
>> > 3d app goes kerblam)
>> 
>> How about LinuxBIOS + Kernel ===> Final kernel path?
>> someday EFI(PEI) + Kernel ===> Final kernel path need that too.
>> 
>> or the normal kexec path still could have clean shutdown.
>
> The kexec path for kdump should be swiotlb and leave the GART alone as
> you are dumping as much state as you can and leaving stuff as is when
> possible. The new-kernel case you shut everything down so you can shut
> down the GART in the old kernel and re-initialise it in the new one

Agreed.

Eric