From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: Runtime PM status sysfs attribute Date: Thu, 1 Jul 2010 23:13:41 +0200 Message-ID: <201007012313.41826.rjw@sisk.pl> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: linux-pm@lists.linux-foundation.org Cc: Dominik Brodowski List-Id: linux-pm@vger.kernel.org On Thursday, July 01, 2010, Alan Stern wrote: > On Thu, 1 Jul 2010, Dominik Brodowski wrote: > > > Alan, > > > > On Thu, Jul 01, 2010 at 01:16:31PM -0400, Alan Stern wrote: > > > As runtime PM becomes more and more popular, it seems likely that > > > people will want to know whether or not their devices are getting > > > suspended. Or if not people, then programs like powertop. > > > > > > For that reason, it seems to make sense to build the runtime_status > > > sysfs attribute even when CONFIG_PM_ADVANCED_DEBUG isn't enabled. Do > > > you agree? > > > > good idea; haven't looked at any dependencies yet, though... > > Reading through the code shows there is a drawback: For subsystems that > don't implement runtime PM, devices will always show up as "suspended". > That's not going to be very useful, unfortunately. > > Still, for subsystems that _do_ implement runtime PM, there doesn't > seem to be any other way to learn the current status of a device. Perhaps we can rework the attribute to show "unknown" for devices that have power.disable_depth > 0 ? Rafael