linux-kernel - Re: [PATCH] PM Sleep: Don't extend wakeup paths to devices with ignore

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Date:	Thu, 17 Nov 2011 21:16:07 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Greg KH <gregkh@...e.de>
Cc:	Linux PM list <linux-pm@...r.kernel.org>,
	"Linux-sh list" <linux-sh@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Magnus Damm <magnus.damm@...il.com>
Subject: Re: [PATCH] PM Sleep: Don't extend wakeup paths to devices with ignore_children set

On Thursday, November 17, 2011, Greg KH wrote:
> On Wed, Nov 16, 2011 at 11:21:58PM +0100, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rjw@...k.pl>
> > 
> > Commit 4ca46ff3e0d8c234cb40ebb6457653b59584426c (PM / Sleep: Mark
> > devices involved in wakeup signaling during suspend) introduced
> > the power.wakeup_path field in struct dev_pm_info to mark devices
> > whose children are enabled to wake up the system from sleep states,
> > so that power domains containing the parents that provide their
> > children with wakeup power and/or relay their wakeup signals are not
> > turned off.  Unfortunately, that introduced a PM regression on SH7372
> > whose power consumption in the system "memory sleep" state increased
> > as a result of it, because it prevented the power domain containing
> > the I2C controller from being turned off when some children of that
> > controller were enabled to wake up the system, although the
> > controller was not necessary for them to signal wakeup.
> > 
> > To fix this issue use the observation that devices whose
> > power.ignore_children flag is set for runtime PM should be treated
> > analogously during system suspend.  Namely, they shouldn't be
> > included in wakeup paths going through their children.  Since the
> > SH7372 I2C controller's power.ignore_children flag is set, doing so
> > will restore the previous behavior of that SOC.
> > 
> > Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
> 
> Acked-by: Greg Kroah-Hartman <gregkh@...e.de>

Thanks!
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