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From: Josh Boyer <jwboyer@linux.vnet.ibm.com>
To: jyoung5@us.ibm.com
Cc: kvm-ppc-devel@lists.sourceforge.net, linuxppc-dev@ozlabs.org,
	Hollis Blanchard <hollisb@us.ibm.com>
Subject: Re: [kvm-ppc-devel] [PATCH] Add idle power save for ppc 4xx
Date: Mon, 31 Mar 2008 12:48:14 -0500	[thread overview]
Message-ID: <20080331124814.4ebfc405@zod.rchland.ibm.com> (raw)
In-Reply-To: <1206982322.9165.7.camel@thinkpadL>

On Mon, 31 Mar 2008 11:52:02 -0500
Jerone Young <jyoung5@us.ibm.com> wrote:

> > void ppc4xx_idle(void)
> > 
> > > +{
> > > +	unsigned long msr_save;
> > > +
> > > +	/* set wait state MSR */
> > > +	local_irq_enable();
> > > +	msr_save = mfmsr();
> > > +	mtmsr(msr_save|MSR_WE);
> > 
> > Why don't you |MSR_WE|MSR_EE at the same time?
> 
> You technically can do this. But the question is do all 4xx cpus use
> MSR_EE to enable interrupts? I can assume they do (from what I know),

They do for enabling external interrupts of normal priority.  MSR_CE
might also be used/needed if someone has the watchdog enabled or has an
external device with the UIC pin mapped as a CE.

josh

  reply	other threads:[~2008-03-31 17:52 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-31 13:12 [PATCH] Add idle power save for ppc 4xx Jerone Young
2008-03-31 16:27 ` [kvm-ppc-devel] " Hollis Blanchard
2008-03-31 16:52   ` Jerone Young
2008-03-31 17:48     ` Josh Boyer [this message]
2008-04-01 12:14     ` Arnd Bergmann
2008-03-31 17:07 ` Josh Boyer
2008-03-31 18:05   ` Josh Boyer
2008-03-31 18:19     ` Jerone Young
2008-04-01  1:04       ` Michael Ellerman
2008-04-01  3:15         ` Josh Boyer
2008-04-01  3:30           ` Michael Ellerman
2008-04-01 12:01           ` [kvm-ppc-devel] " Jimi Xenidis
2008-04-01 12:03             ` Josh Boyer
2008-03-31 19:24     ` Hollis Blanchard
2008-03-31 20:28       ` Josh Boyer
2008-03-31 20:34         ` Hollis Blanchard
2008-04-01  4:00     ` Paul Mackerras
2008-04-01 11:03       ` Josh Boyer
2008-03-31 18:23   ` Jerone Young
2008-03-31 19:11     ` Josh Boyer

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