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Groups > linux.kernel > #1586116

Re: LED devices & poll() for brightness attribute

From Pavel Machek <pavel@ucw.cz>
Newsgroups linux.kernel
Subject Re: LED devices & poll() for brightness attribute
Date 2017-02-22 13:30 +0100
Message-ID <tdEds-1BM-11@gated-at.bofh.it> (permalink)
References <tdB5T-7N5-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Hi!

> But this support is useful just for one single central userspace
> application which will control all leds in system other application
> which will change state by /sys/class/leds/ will de-synchronize that one
> central application.

Yes. Does it matter for some real use case?

> So I think new ABI is not sufficient and I would propose to add poll()
> support also for changes done by userspace, write() to attribute
> /sys/class/leds/.../brightness.

Not easily possible, as we have triggers, and this was discussed in
great great lengths before. Please go through that discussion.
								Pavel
									
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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Thread

LED devices & poll() for brightness attribute Pali Rohár <pali.rohar@gmail.com> - 2017-02-22 10:10 +0100
  Re: LED devices & poll() for brightness attribute Pavel Machek <pavel@ucw.cz> - 2017-02-22 13:30 +0100
    Re: LED devices & poll() for brightness attribute Pali Rohár <pali.rohar@gmail.com> - 2017-02-22 13:50 +0100
      Re: LED devices & poll() for brightness attribute Pavel Machek <pavel@ucw.cz> - 2017-02-22 22:00 +0100
        Re: LED devices & poll() for brightness attribute Pali Rohár <pali.rohar@gmail.com> - 2017-02-22 22:20 +0100
          Re: LED devices & poll() for brightness attribute Pavel Machek <pavel@ucw.cz> - 2017-02-23 15:40 +0100
            Re: LED devices & poll() for brightness attribute Pali Rohár <pali.rohar@gmail.com> - 2017-02-23 15:50 +0100
              Re: LED devices & poll() for brightness attribute Pavel Machek <pavel@ucw.cz> - 2017-02-23 21:30 +0100
                Re: LED devices & poll() for brightness attribute Pali Rohár <pali.rohar@gmail.com> - 2017-02-23 21:50 +0100
                Re: LED devices & poll() for brightness attribute Pavel Machek <pavel@ucw.cz> - 2017-02-23 22:20 +0100
                Re: LED devices & poll() for brightness attribute Pali Rohár <pali.rohar@gmail.com> - 2017-02-24 10:00 +0100
                Re: LED devices & poll() for brightness attribute Pali Rohár <pali.rohar@gmail.com> - 2017-02-24 10:00 +0100
                Re: LED devices & poll() for brightness attribute Hans de Goede <hdegoede@redhat.com> - 2017-02-24 10:00 +0100

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