From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon
 panic
Date: Thu, 03 Feb 2011 13:07:02 -0800
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To: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Machek <pavel@ucw.cz>, Tejun Heo <tj@kernel.org>, "Ahmed S. Darwish" <darwish.07@gmail.com>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, X86-ML <x86@kernel.org>, Tony Luck <tony.luck@intel.com>, Dave Jones <davej@redhat.com>, Andrew Morton <akpm@linux-foundation.org>, Randy Dunlap <rdunlap@xenotime.net>, Willy Tarreau <wtarreau@hera.kernel.org>, Willy Tarreau <w@1wt.eu>, Dirk Hohndel <hohndel@infradead.org>, Dirk.Hohndel@intel.com, IDE-ML <linux-ide@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>, Linus Torvalds <torvalds@linux-foundation.org>, Peter Zijlstra <a.p.zijlstra@chello.nl>, Fr?d?ric Weisbecker <fweisbec@gmail.com>, Borislav Petkov <bp@alien8.de>, Arjan van de Ven <arjan@infradead.org>

On 02/03/2011 09:57 AM, Ingo Molnar wrote:
> 
> * H. Peter Anvin <hpa@zytor.com> wrote:
> 
>> On 02/03/2011 06:36 AM, Pavel Machek wrote:
>>>
>>> Could we read the log area, first, verify it contains signature, write
>>> it back?
>>> 								Pavel
>>
>> Yes, but that doesn't guarantee no data corruption caused by handing
>> over from one driver to another.
> 
> Waiting a few seconds? Is there any sufficiently high number of X where waiting X 
> seconds would make it safe to touch the hardware? (i.e. it would guarantee that 
> pending commands are flushed, etc.)
> 

Probably not... if you have enough control over the hardware to force a
device reset you should be okay, though.  This kind of comes down to
wanting a complete set of system drivers, i.e. kexec/kdump again.

	-hpa