From: Rusty Russell <rusty@rustcorp.com.au>
To: Dave Jones <davej@redhat.com>
Subject: Re: Warning during suspend with MS-7310 mainboard
Date: Fri, 31 Jul 2009 08:37:22 +0930
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Cc: "Langsdorf, Mark" <mark.langsdorf@amd.com>,
       Eric Sesterhenn <eric.sesterhenn@lsexperts.de>,
       linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org
References: <1248936650.3313.6.camel@queen> <6453C3CB8E2B3646B0D020C11261327303620A01@sausexmb4.amd.com> <20090730164629.GC2593@redhat.com>
In-Reply-To: <20090730164629.GC2593@redhat.com>
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On Fri, 31 Jul 2009 02:16:29 am Dave Jones wrote:
> On Thu, Jul 30, 2009 at 11:38:22AM -0500, Langsdorf, Mark wrote:
>  > I'll look into it.
>  > 
>  > First time I've had this bug reported, though.
>  > 
> 
> It's happening because the suspend code runs with interrupts disabled,
> and the powerpc workaround we do in the cpufreq suspend hook
> calls the drivers ->get method.
> 
> powernow-k8's ->get does an smp_call_function_single
> which needs interrupts enabled

Yeah, I was confused: my patch changed set_cpus_allowed_ptr() to
an smp_call_function.  If the latter is a bad idea with irqs disabled, the
former certainly was...

Thanks,
Rusty.
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