linux-kernel - Re: [PATCH] ACPI / PM: Infer parent power state from child if unknown

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Message-Id: <201209112236.31954.rjw@sisk.pl>
Date:	Tue, 11 Sep 2012 22:36:31 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Aaron Lu <aaron.lu@...el.com>
Cc:	Len Brown <lenb@...nel.org>, linux-acpi@...r.kernel.org,
	linux-pm@...r.kernel.org, Aaron Lu <aaron.lwe@...il.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPI / PM: Infer parent power state from child if unknown

On Tuesday, September 11, 2012, Aaron Lu wrote:
> On Mon, Sep 10, 2012 at 09:50:22PM +0200, Rafael J. Wysocki wrote:
> >  drivers/acpi/bus.c |   11 ++++++++++-
> >  1 file changed, 10 insertions(+), 1 deletion(-)
> > 
> > Index: linux/drivers/acpi/bus.c
> > ===================================================================
> > --- linux.orig/drivers/acpi/bus.c
> > +++ linux/drivers/acpi/bus.c
> > @@ -228,7 +228,16 @@ static int __acpi_bus_get_power(struct a
> >  		result = psc;
> >  	}
> >  	/* The test below covers ACPI_STATE_UNKNOWN too. */
> > -	if (result <= ACPI_STATE_D2) {
> > +	if (result == ACPI_STATE_D0) {
> 
> Oops, I just realized that the check here is too early if device does
> not have _PSC but _PRx, its parent will miss the chance to get power
> state updated :-)

Ah, right.  I'll post an update in a minute.

> Sorry for not spotting this earlier.

Well, I should have figured that myself too. ;-)

Thanks,
Rafael
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