From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: a question about lid input device Date: Wed, 7 Jul 2010 10:01:25 -0700 Message-ID: <20100707170125.GB25178@core.coreip.homeip.net> References: <1276412011.19052.19294.camel@rzhang1-desktop> <20100614020127.GA30773@khazad-dum.debian.net> <8005.1278515660@foxharp.boston.ma.us> <20100707162511.GA25178@core.coreip.homeip.net> <16574.1278521464@foxharp.boston.ma.us> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:54601 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757352Ab0GGRBd (ORCPT ); Wed, 7 Jul 2010 13:01:33 -0400 Received: by pzk26 with SMTP id 26so1171104pzk.19 for ; Wed, 07 Jul 2010 10:01:32 -0700 (PDT) Content-Disposition: inline In-Reply-To: <16574.1278521464@foxharp.boston.ma.us> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Paul Fox Cc: Henrique de Moraes Holschuh , Zhang Rui , "linux-acpi@vger.kernel.org" , "Brown, Len" On Wed, Jul 07, 2010 at 12:51:04PM -0400, Paul Fox wrote: > dmitry wrote: > > On Wed, Jul 07, 2010 at 11:14:20AM -0400, Paul Fox wrote: > > > henrique de moraes holschuh wrote: > > > > On Sun, 13 Jun 2010, Zhang Rui wrote: > > > > > Then we update the lid switch status when a Lid notification comes. > > > > > right? > > > > > > > > Yes. > > > > > > > > > Then, IMO, userspace can get the lid status > > > > > via /sys/class/input/inputX/uevent, right? > > > > > > > > No, only through an IOCTL. > > > > > > > > > /sys/class/input/input1/uevent:EV==21 > > > > > > > > That's an bitmap of al EV_EV it supports. > > > > > > > > > /sys/class/input/input1/uevent:SW==1 > > > > > > > > That's an bitmap of al EV_SW it supports. > > > > > > > > > Lid is opened but SW is set, I tried to close/open the lid and found > > > > > that this bit never changes. is there something I misunderstand? can we > > > > > get the lid status in userspace? > > > > > > > > IOCTL(), only. > > > > > > > > Since nobody got a input-utils standard package (or added something to > > > > util-linux) yet to do that (AFAIK anyway), it is a MAJOR annoyance for > > > > shell scripts that want to query EV_SW state... > > > > > > i understand that it's not fully general, but for the case of > > > the lid: is /proc/acpi/button/lid/LID/state going away? > > > > > > > Yes, according to feature-removal.txt ACPI procfs interface shoudl have > > been gone back in 2008. > > thanks. i understand that adding sysfs entries for all the bells > and whistles on modern input devices might seem prohibitive. on > the other hand, there are some basic interfaces that are very > usefully accessed from the shell. i guess either way the > information is available, but having to rely on a utility package > for intermediate access always introduces new packaging > dependencies, release skew issues, etc, etc. > I am not wasting kernel memory to export full state of an arbitrary input device via sysfs just so someone out there might avoid writing or installig a utility. The interface was there for many years and is quite stable, I do not understand what release skew issues you are talking about. Thanks. -- Dmitry