linux-kernel - Re: [BUG]: DELL XPS 8500 become a brick after fill too many entries to nvram.

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Message-ID: <20131113112052.GJ22636@console-pimps.org>
Date:	Wed, 13 Nov 2013 11:21:23 +0000
From:	Matt Fleming <matt@...sole-pimps.org>
To:	Madper Xie <cxie@...hat.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	Matt Fleming <matt.fleming@...el.com>
Subject: Re: [BUG]: DELL XPS 8500 become a brick after fill too many entries
 to nvram.

On Mon, 11 Nov, at 08:38:31PM, Madper Xie wrote:
> 
> matt@...sole-pimps.org writes:
> 
> > On Mon, 11 Nov, at 02:15:22PM, Madper Xie wrote:
> >> Howdy all,
> >>   For now we ensure at least ~5kb free space. But my dell xps still
> >>   become a brick after I add too many entries to my nvram. So maybe 5kb
> >>   is not safe enough. and 5kb is just aginst Samsung's laptop.
> >>   So should we enlarge EFI_MIN_RESERVE?
> >
> > Urgh.............
> >
> > Thanks for the report. Could you provide some more details?
> >
> >  - Is your machine definitely bricked?
> Yes, pretty sure. After I press power button, the screen shows "DELL"
> and hangs. I can't step into any configure interface and the keyboard is
> dead. (NumLock led on, and I can't turn it off.) Of course my kernel
> won't be loaded. The only way to fix it is change the jump line which is
> on the motherboard.

OK, that's pretty conclusive. Thanks.

> >  - Have you got a dmesg from the machine before it broke?
> No. But with a diagnostic kernel(without change the behavior of
> efi. Simply print total size and remain size when I write something to
> nvram. Provided by Lenny), I got following output:
 
Have you been able to calculate the safe limit of NVRAM we need to
reserve to avoid bricking your machine?

I was interested in the DMI and other firmware strings from dmesg.

-- 
Matt Fleming, Intel Open Source Technology Center
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