Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753839AbZCBObs (ORCPT ); Mon, 2 Mar 2009 09:31:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751958AbZCBObj (ORCPT ); Mon, 2 Mar 2009 09:31:39 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:36030 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751948AbZCBObi (ORCPT ); Mon, 2 Mar 2009 09:31:38 -0500 Date: Mon, 2 Mar 2009 15:34:22 +0100 From: Pavel Machek To: Oliver Neukum Cc: Arve Hj?nnev?g , "Rafael J. Wysocki" , Alan Stern , "Woodruff, Richard" , Arjan van de Ven , Kyle Moffett , Benjamin Herrenschmidt , pm list , LKML , Nigel Cunningham , Matthew Garrett , mark gross , Uli Luckas , Igor Stoppa , Brian Swetland , Len Brown Subject: Re: [RFD] Automatic suspend Message-ID: <20090302143422.GE2527@elf.ucw.cz> References: <20090301225647.GE1961@elf.ucw.cz> <200903020924.42451.oliver@neukum.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <200903020924.42451.oliver@neukum.org> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2250 Lines: 57 On Mon 2009-03-02 09:24:36, Oliver Neukum wrote: > Am Sonntag 01 M?rz 2009 23:56:47 schrieb Pavel Machek: > > > Allowing user space to suspend input devices while they are still open > > > is useful. The user-space code that reads from the input devices does > > > not need to know if the device is suspended or not, and the kernel > > > cannot auto suspend input devices based on inactivity. > > > > Actually, I'd like you to fix your userspace and close input devices > > when it does not need them. Given the way you control the platform it > > should not be that hard. I do not see why we'd want to invent new > > interface for "uhuh, I have opened the keyboard but I am not really > > interested in keys being pressed". > > Generally you can't do this. A task has an open fd. > > - you cannot assume it can open the device again (fd may be > inherited) Well, those tasks that matter - X servers and similar - usually can. > - keeping the device open makes sure you are talking to the same device Well, you have to handle hotplug anyway, so... and the name will not change unless you unplug/replug. > - you may want to avoid repeating expensive initialisations That kind of initializations should perhaps be done at insmod, not open time? > - some input devices also do output I guess you want to separate those to two different devices, then. Anyway... * I'd prefer "close to powersave". I can see that can be tricky to use. So the alternative is * ioctl() "I'm not interested in exact keys, powersave" is something that makes sense. It should really be discussed with input people. I'd hate to see * magic /sys/.../file where you echo 1 to powersave. It is too disconnected from the input fd, and while it may make it easier to retrofit powermanagement without modifying Xservers etc... it will ultimately result in pretty ugly hacks. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/