linux-kernel - Re: [2.6.25-rc5-mm1] BUG: spinlock bad magic early during boot

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Date:	Fri, 21 Mar 2008 14:17:38 +0100
From:	Pavel Machek <pavel@....cz>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	?ric Piel <Eric.Piel@...mplin-utc.net>,
	Tilman Schmidt <tilman@...p.cc>,
	Dave Hansen <haveblue@...ibm.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, Thomas Renninger <trenn@...e.de>,
	Len Brown <len.brown@...el.com>,
	Christoph Hellwig <hch@...radead.org>,
	Markus Gaugusch <dsdt@...gusch.at>, linux-acpi@...r.kernel.org,
	Al Viro <viro@...IV.linux.org.uk>,
	Arjan van de Ven <arjanv@...hat.com>
Subject: Re: [2.6.25-rc5-mm1] BUG: spinlock bad magic early during boot

Hi!

> > It's a pity, I had just nearly finished a new approach. Instead of
> > relying on populate_rootfs() and the filesystem infrastructure, the new
> > approach directly finds the file in the initramfs.
> 
> So that avoids the VFS layer issues, but it's still strictly much worse 
> than just having a run-time loading.
> 
> What's the problem with just loading a new DSDT later? Potentially as in 
> *much* later: including when user-space is all up-and-running? 
> 
> For things like DVD install images, you'd quite possibly want to have a 
> few known-workaround DSDT images with the installer, and just say "ok, we 
> want to fix up this ACPI crap in order to get working suspend/resume" kind 
> of thing.
> 
> So what's the reason for pushing for this insanely-early workaround in the 
> first place, instead of letting user-space do something like
> 
> 	cat my-dsdt-image > /proc/sys/acpi/DSDT
> 
> or whatever at runtime?

You have interpretted code runing (AML), and you want to replace it
with different code?

Akin to changing from one kernel to different during runtime?

Yes, I guess it might work for very simple changes, but if you need to change
data structures between origina and modified DSDT, you are in for a
big trouble, right?
							Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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