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Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing runtime suspend

From "Rafael J. Wysocki" <rjw@rjwysocki.net>
Newsgroups linux.kernel
Subject Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing runtime suspend
Date 2015-09-09 22:10 +0200
Message-ID <q6TQS-4VR-17@gated-at.bofh.it> (permalink)
References <q6PtW-717-59@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Wednesday, September 09, 2015 11:20:25 AM Alan Stern wrote:
> On Wed, 9 Sep 2015, Rafael J. Wysocki wrote:
> 
> > > The best example and actually the very specific problem we want to
> > > solve is handling touchscreens on a phone / tablet. When the screen is
> > > turned off, it is ideal to suspend the touchscreen for two reasons: to
> > > lower the power consumption as much as possible and to prevent
> > > interrupts to wake-up the CPU when the user touches the device, and
> > > thus save even more power as we allow the CPU to stay in deep idle
> > > states for longer periods.
> > >
> > > Note that when the screen is turned-on again, we want to resume the
> > > touchscreen so that it can send events again.
> > 
> > In fact, then, what you need seems to be the feature discussed by Alan
> > and me some time ago allowing remote wakeup do be disabled for runtime
> > PM from user space as that in combination with autosuspend should
> > address your use case.
> 
> That, plus they want the touchscreen to go into runtime suspend 
> whenever the screen is off (was this not the main reason for the 
> patch?).

Right.

> It seems to me that it should be possible to arrange for this to happen 
> simply by making userspace close the touchscreen device when the screen 
> is turned off.  Or am I missing something?

Honestly, I don't know.

Octavian, Irina, any reasons why things can't be done as Alan is suggesting?

Thanks,
Rafael

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[RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing runtime suspend Irina Tirdea <irina.tirdea@intel.com> - 2015-09-07 22:50 +0200
  Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing runtime suspend "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-09-07 23:00 +0200
    RE: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend "Tirdea, Irina" <irina.tirdea@intel.com> - 2015-09-08 03:20 +0200
      Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Oliver Neukum <oneukum@suse.com> - 2015-09-08 09:40 +0200
        Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend "Rafael J. Wysocki" <rafael@kernel.org> - 2015-09-08 23:00 +0200
          Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Ulf Hansson <ulf.hansson@linaro.org> - 2015-09-09 00:30 +0200
            Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend "Rafael J. Wysocki" <rafael@kernel.org> - 2015-09-09 02:00 +0200
              Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Octavian Purdila <octavian.purdila@intel.com> - 2015-09-09 13:20 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend "Rafael J. Wysocki" <rafael@kernel.org> - 2015-09-09 14:30 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Oliver Neukum <oneukum@suse.com> - 2015-09-09 16:00 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Octavian Purdila <octavian.purdila@intel.com> - 2015-09-09 17:10 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing runtime suspend "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-09-09 22:00 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Oliver Neukum <oneukum@suse.com> - 2015-09-10 11:50 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Pavel Machek <pavel@ucw.cz> - 2015-09-21 14:30 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Alan Stern <stern@rowland.harvard.edu> - 2015-09-09 17:30 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing runtime suspend "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-09-09 22:10 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Colin Cross <ccross@google.com> - 2015-09-09 22:20 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Pavel Machek <pavel@ucw.cz> - 2015-09-21 14:40 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Alan Stern <stern@rowland.harvard.edu> - 2015-09-21 16:40 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-09-21 18:20 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Alan Stern <stern@rowland.harvard.edu> - 2015-09-21 18:40 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-09-21 19:00 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Alan Stern <stern@rowland.harvard.edu> - 2015-09-21 19:40 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-09-21 20:10 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Alan Stern <stern@rowland.harvard.edu> - 2015-09-21 22:10 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-09-21 23:00 +0200
                Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Pavel Machek <pavel@ucw.cz> - 2015-09-21 22:30 +0200
      RE: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Alan Stern <stern@rowland.harvard.edu> - 2015-09-08 16:50 +0200
        Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing runtime suspend "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2015-09-08 16:50 +0200
          Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Alan Stern <stern@rowland.harvard.edu> - 2015-09-08 17:10 +0200
            Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend "Rafael J. Wysocki" <rafael@kernel.org> - 2015-09-08 22:30 +0200
              Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Alan Stern <stern@rowland.harvard.edu> - 2015-09-09 17:30 +0200
        Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Oliver Neukum <oneukum@suse.com> - 2015-09-09 08:30 +0200
          Re: [RFC PATCH] PM / Runtime: runtime: Add sysfs option for forcing  runtime suspend Alan Stern <stern@rowland.harvard.edu> - 2015-09-09 16:40 +0200

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