From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Stern Subject: Re: [RFC][PATCH 00/11] Android PM extensions Date: Mon, 2 Feb 2009 10:05:00 -0500 (EST) Message-ID: References: <200902021142.15092.u.luckas@road.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200902021142.15092.u.luckas@road.de> 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: Uli Luckas Cc: swetland@google.com, linux-pm@lists.linux-foundation.org, Nigel Cunningham List-Id: linux-pm@vger.kernel.org On Mon, 2 Feb 2009, Uli Luckas wrote: > Hi Alan, > we have had a (userspace) wake-lock implementation on our handyPC devices for > a couple of years now. So maybe I can shed some light. > > The above quote underlines pretty well, where Arve's and your ideas of > eraly-suspend and wake-locks diverge. And why you are missunderstanding each > other. > Arve is always talking about "blanking the screen" because that's what the > users sees. From the user's perspective the device is "suspended" as soon as > his user interfaces vanishes. That's probably also why his notions > of "suspend" and "wake" are not alway following a strict definition. And that's partly why I have been complaining about the things he writes. To a kernel programmer, "suspend" has a very specific meaning, quite different from what it might mean to a user. When Arve posts on a kernel-oriented mailing list, he should use such words in a way his readers will understand. > If the device stays blanked while the user has his 10 min phone conversation, > then he won't even notice wether the device suspends or not after the call. > This is the idea. The user does not care for anything they can't see. > > Arve is not talking about a laptop that needs to sleep befor it's ventilation > slot are covered. He is talking about a phone that could well do with only > blanking it's screen. Except it want's to save battery when ever possible. The problem is that he's talking about making changes to a kernel that will be installed in all sorts of machines, from phones all the way up to supercomputers. When you do this, you have to broaden your point of view -- your code has to run correctly in all of these settings. Alan Stern