From: Andi Kleen <ak@suse.de>
To: michael@ellerman.id.au
Cc: linux-kernel@vger.kernel.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [RFC/PATCH] Make printk work for really early debugging
Date: Thu, 18 May 2006 18:00:21 +0200 [thread overview]
Message-ID: <200605181800.21829.ak@suse.de> (raw)
In-Reply-To: <1147966886.8469.4.camel@localhost.localdomain>
On Thursday 18 May 2006 17:41, Michael Ellerman wrote:
> On Thu, 2006-05-18 at 15:55 +0200, Andi Kleen wrote:
> > Michael Ellerman <michael@ellerman.id.au> writes:
> >
> > > Currently printk is no use for early debugging because it refuses to actually
> > > print anything to the console unless cpu_online(smp_processor_id()) is true.
> >
> > On x86-64 this is simply solved by setting the boot processor online very early.
>
> Yeah, someone suggested that. Unfortunately it doesn't work, we actually
> want to call printk before we even know which cpu we're on :D
You mean smp_processor_id() returns a random value?
Then your patch is broken too because iirc it tested smp_processor_id()
before that other flag
-Andi
next prev parent reply other threads:[~2006-05-18 16:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-18 9:14 [RFC/PATCH] Make printk work for really early debugging Michael Ellerman
2006-05-18 9:34 ` Andrew Morton
2006-05-18 9:55 ` Michael Ellerman
2006-05-18 10:07 ` Andrew Morton
2006-05-22 6:40 ` Michael Ellerman
2006-05-18 13:55 ` Andi Kleen
2006-05-18 15:41 ` Michael Ellerman
2006-05-18 16:00 ` Andi Kleen [this message]
2006-05-19 4:15 ` Michael Ellerman
2006-05-22 6:57 ` Michael Ellerman
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