From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [linux-pm] [RFC] input: syfs switches for SKE keypad Date: Wed, 6 Oct 2010 11:26:47 -0700 Message-ID: <20101006182647.GA5794@core.coreip.homeip.net> References: <201010061018.14714.dmitry.torokhov@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:60492 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932956Ab0JFS0z (ORCPT ); Wed, 6 Oct 2010 14:26:55 -0400 Received: by pzk34 with SMTP id 34so2017349pzk.19 for ; Wed, 06 Oct 2010 11:26:54 -0700 (PDT) Content-Disposition: inline In-Reply-To: Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Alan Stern Cc: Trilok Soni , samu.p.onkalo@nokia.com, Linus WALLEIJ , Naveen Kumar GADDIPATI , "linux-pm@lists.osdl.org" , "linux-input@vger.kernel.org" , Jayeeta BANDYOPADHYAY , ext Sundar R IYER On Wed, Oct 06, 2010 at 02:19:03PM -0400, Alan Stern wrote: > On Wed, 6 Oct 2010, Dmitry Torokhov wrote: > > > > > I think last time Rafael mentioned that runtime PM did not allow for > > > > forcing power state from userspace but I wonder if it would be possible > > > > for userspace to signal and "accelerate" the idle state for a device and > > > > then standard runtime PM framework would kick in... > > > > > > Yes; drivers can implement their runtime power policy any way they > > > want. For example, a driver could create a sysfs attribute file which > > > userspace could use to ask for changes in the power state. > > > > > > The real question is whether the driver is platform-specific. If it is > > > then fine, it can do whatever it wants. If it isn't then it should > > > try to avoid doing things that are tied to a specific platform. > > > > > > > No, I really think it is wrong. This what leads us to the situation we > > are in at the moment. Every device [re]implements its own little knobs > > to do power management. Accelerometers export their (often tailored to a > > specific platform) attributes in sysfs in nonstandard way. And so on, > > and so forth. > > > > Here I'd like to see these (PM) hooks done on device core level, i.e. > > the knobs should be unified and live in /sys/devices/.../deviceX/power/ > > I haven't followed this thread in detail. What sort of knobs are you > talking about? That is, what needs to be done? Maybe the PM core > already provides these features. > Mobile folks wish to power down some devices (most often input - touchscreen, keypad) under certain circumstances to save power. So far they were doing that by adding "disable" hook to individual drivers and while I did allow that in for some devices I feel that we need more standardised solution, preferably one that could re-use existing PM hooks in drivers. -- Dmitry