Re: Suspend on Dell D420
From: Andrew Morton
Date: Fri Aug 04 2006 - 18:15:58 EST
On Fri, 4 Aug 2006 23:27:38 +0200
"Rafael J. Wysocki" <rjw@xxxxxxx> wrote:
> On Friday 04 August 2006 18:23, Steinar H. Gunderson wrote:
> > [Please Cc me on any followups]
> > Hi,
> > Suspend-to-RAM works fine on my new Dell Latitude D420 (with Core Duo) in
> > 2.6.16, but it broke in 2.6.17 -- the machine suspends just fine, but when it
> > resumes, the disk never spins up, the screen stays black and it just hangs.
> > Bisecting shows that the following commit is where it broke:
> > commit 78eef01b0fae087c5fadbd85dd4fe2918c3a015f
> > Author: Andrew Morton <akpm@xxxxxxxx>
> > Date: Wed Mar 22 00:08:16 2006 -0800
> > [PATCH] on_each_cpu(): disable local interrupts
> > When on_each_cpu() runs the callback on other CPUs, it runs with local
> > interrupts disabled. So we should run the function with local interrupts
> > disabled on this CPU, too.
> > And do the same for UP, so the callback is run in the same environment on both
> > UP and SMP. (strictly it should do preempt_disable() too, but I think
> > local_irq_disable is sufficiently equivalent).
> > Also uninlines on_each_cpu(). softirq.c was the most appropriate file I could
> > find, but it doesn't seem to justify creating a new file.
> > Oh, and fix up that comment over (under?) x86's smp_call_function(). It
> > drives me nuts.
> > Applying the patch in reverse against 2.6.17 (it doesn't apply cleanly, but
> > I've done what seems to be the moral equivalent) makes the suspend work
> > again.
> > Any ideas? It does not work with the latest git checkout as of today.
> I guess the patch may interfere with the CPU hotplug badly.
Why do you think it would do that?
> Could you please
> check if you can take CPU1 offline/online?
If something really wants "disable irqs on the other CPUs but not on this
CPU" semantics then it would need to use smp_call_function and a direct
call. But it would be a strange thing to want to do, surely?
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