From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: min/max and actual values on absolute axes Date: Mon, 29 Jun 2009 21:53:54 -0700 Message-ID: <20090630045354.GG10652@dtor-d630.eng.vmware.com> References: <20090629234258.GA30771@dingo.bne.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from rv-out-0506.google.com ([209.85.198.230]:61474 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750990AbZF3Exz (ORCPT ); Tue, 30 Jun 2009 00:53:55 -0400 Received: by rv-out-0506.google.com with SMTP id k40so1182514rvb.5 for ; Mon, 29 Jun 2009 21:53:58 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20090629234258.GA30771@dingo.bne.redhat.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Peter Hutterer Cc: linux-input@vger.kernel.org Hi Peter, On Tue, Jun 30, 2009 at 09:42:58AM +1000, Peter Hutterer wrote: > Hi guys, > > A question regarding min/max values on absolute axes of input devices. I > have a few bugreports related to the synaptics driver and the trigger for > the bug are coordinates outside the min/max range. > > Example evtest output: http://bugs.freedesktop.org/attachment.cgi?id=27229 > > Event type 3 (Absolute) > Event code 0 (X) > Value 6044 > Min 1472 > Max 5472 > Event code 1 (Y) > Value 1261 > Min 1408 > Max 4448 > > > From Documentation/input/input-programming: > "This setting would be appropriate for a joystick X axis, with the minimum of > 0, maximum of 255 (which the joystick *must* be able to reach, no problem if > it sometimes reports more, but it must be able to always reach the min and > max values), [...]" > > Do I read this correct that min/max is intended as guideline only and cannot > be relied on for actual coordinate boundaries? > That is correct. Input core does not perform any "snapping" of the reported coordinates to the min/max boundaries, these values are advisory only. -- Dmitry