From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752452Ab1LAGTD (ORCPT ); Thu, 1 Dec 2011 01:19:03 -0500 Received: from mga14.intel.com ([143.182.124.37]:21337 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751641Ab1LAGTB (ORCPT ); Thu, 1 Dec 2011 01:19:01 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,276,1320652800"; d="scan'208";a="42789073" Date: Thu, 1 Dec 2011 14:19:48 +0800 From: Feng Tang To: Dmitry Torokhov CC: "linux-input@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Clark, Joel" Subject: Re: [PATCH 2/2] Input: tsc2007 - Add a z1_low_threshhold platform data parameter Message-ID: <20111201141948.13162071@feng-i7> In-Reply-To: <20111201054726.GC16816@core.coreip.homeip.net> References: <1322554378-348-1-git-send-email-feng.tang@intel.com> <1322554378-348-2-git-send-email-feng.tang@intel.com> <20111129092310.GB21758@core.coreip.homeip.net> <20111130103418.4514b630@feng-i7> <20111201054726.GC16816@core.coreip.homeip.net> Organization: intel X-Mailer: Claws Mail 3.7.6 (GTK+ 2.22.0; i486-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 1 Dec 2011 13:47:26 +0800 Dmitry Torokhov wrote: > On Wed, Nov 30, 2011 at 10:34:18AM +0800, Feng Tang wrote: > > On Tue, 29 Nov 2011 17:23:10 +0800 > > Dmitry Torokhov wrote: > > > > > On Tue, Nov 29, 2011 at 04:12:58PM +0800, Feng Tang wrote: > > > > This originates from a patch in Meego IVI kernel with the name > > > > linux-2.6.37-connext-0027-tsc2007.patch > > > > There is no author info excepte a line "From MeeGo > > > > " > > > > > > > > When integrating tsc2007 on Intel IVI platform, there are a lot > > > > of noise data whose z1 value is around 10 which is not a sane > > > > "z1". So add a "z1_low_threshhold" to filter those nosie data, > > > > to make the device work properly. > > > > > > Sounds like a task for userspace to ignore pressure that is too > > > low. Bonus points for making it configurable so user can adjust > > > sensitivity. > > > > Actually, there is one more point :), without this patch, the > > driver won't work on our platforms. > > > > The tsc2007_soft_irq will keep reading the input data unless there > > is no valid pressure data. In our case, those noise data will be > > seen as valid data during tsc2007_calculate_pressure(), and the > > tsc2007_soft_irq will run endlessly. > > Even if we add the pressure threshold would not that noise cause > endless stream of interrupts? No, there is no endless interrupts for tsc2007. Without the z1 threshold, the while circle in tsc2007_soft_irq will run endlessly as the noise data will be seen as a valid data: rt = tsc2007_calculate_pressure(ts, &tc); if (rt == 0 && !ts->get_pendown_state) { /* * If pressure reported is 0 and we don't have * callback to check pendown state, we have to * assume that pen was lifted up. */ break; } With the z1 threshold check, the rt will be 0 for noise data, and the code flow broke out. > > Also, what kind of z2 is reported with low z1? And do you implement > get_pendown_state()? z2 seems normal as some data between 3000-4000. We don't have a get_pendown_state(). Thanks, Feng > > Thanks. >