From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Mack Subject: Re: ABS_MAX incrementation? Date: Tue, 4 May 2010 09:18:55 +0200 Message-ID: <20100504071855.GN30801@buzzloop.caiaq.de> References: <20100419171412.GH30801@buzzloop.caiaq.de> <20100419174924.GB22295@core.coreip.homeip.net> <20100419180606.GI30801@buzzloop.caiaq.de> <20100421062929.GH4364@core.coreip.homeip.net> <20100502121331.GH30801@buzzloop.caiaq.de> <20100504065832.GC17482@core.coreip.homeip.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from buzzloop.caiaq.de ([212.112.241.133]:50844 "EHLO buzzloop.caiaq.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753866Ab0EDHTA (ORCPT ); Tue, 4 May 2010 03:19:00 -0400 Content-Disposition: inline In-Reply-To: <20100504065832.GC17482@core.coreip.homeip.net> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Dmitry Torokhov Cc: linux-input@vger.kernel.org Hi Dmitry, On Mon, May 03, 2010 at 11:58:32PM -0700, Dmitry Torokhov wrote: > On Sun, May 02, 2010 at 02:13:31PM +0200, Daniel Mack wrote: > > Hmm, maybe I could also help with that. Could you outline where this > > should go? I guess a linked list is not very suitable as it doesn't > > allow instant access of specific members. So we need a fixed-size bitmap > > to indicate active members at least? > > I was just thinking about having drivers taht emit absolute events > allocate abs data (value, min, max, resolution) separately from > allocating a device (or maybe have additional input_abs_device_alloc > helper). Someting very simple. So that would buy us less memory footprint by saving 4 integers for 1 pointer. However, we would still need to store an array of pointers which has ABS_MAX entries. I'm hessitating as I would like to see ABS_MAX being quite large. I'm planning to write a driver with > 100 absolute axis soon. Also, that approach wouldn't be able to be descriptive about what the axis in fact represent, and especially for such a high number, that would be more than just a nice-to-have :) As I say, I'd be willing to help with this hack up a clean solution which also teaches the user space interface new fancy features. I would just need some idea what's a proper way to go. Thanks, Daniel