From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Purdie Subject: Re: ads7846: clean up, fix pressure reporting Date: Mon, 10 Aug 2009 22:10:48 +0100 Message-ID: <1249938648.22268.190.camel@dax.rpnet.com> References: <20090807180941.GF1728@ucw.cz> <1249813293.4334.24.camel@utx.utx.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1249813293.4334.24.camel@utx.utx.cz> Sender: linux-kernel-owner@vger.kernel.org To: Stanislav Brabec Cc: Pavel Machek , dtor@mail.ru, linux-input@vger.kernel.org, lenz@cs.wisc.edu, kernel list , Dirk@Opfer-Online.de, arminlitzel@web.de, Cyril Hrubis , thommycheck@gmail.com, linux-arm-kernel , dbaryshkov@gmail.com, omegamoon@gmail.com, eric.miao@marvell.com List-Id: linux-input@vger.kernel.org On Sun, 2009-08-09 at 12:21 +0200, Stanislav Brabec wrote: > Pavel Machek wrote: > > Fix pressure reporting, and clean up debug prints. >=20 > Thanks. >=20 > I see much bigger problem with both the old driver and the new ads784= 6 > driver (2.6.30): They are very noisy on my spitz. When you tap to one > place, keep stylus pressed and just read values, you get 20-200 pixel= s > long pointer motion trip each second. >=20 > According to Cyril Hrubi=C5=A1, it is caused by the electrical noise = that > originates in the LCD display. The driver needs to read data > synchronously with the LCD refresh. He already made the fix for colli= e > several years ago. This is what I've been led to believe as well. There was code in the ol= d driver to try and avoid this by only taking touchscreen readings when the LCD wasn't electrically active but it sounds like this has become broken :(. Cheers, Richard --=20 Richard Purdie Intel Open Source Technology Centre