From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261855AbVBIR3z (ORCPT ); Wed, 9 Feb 2005 12:29:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261858AbVBIR3z (ORCPT ); Wed, 9 Feb 2005 12:29:55 -0500 Received: from styx.suse.cz ([82.119.242.94]:29073 "EHLO mail.suse.cz") by vger.kernel.org with ESMTP id S261855AbVBIR3Z (ORCPT ); Wed, 9 Feb 2005 12:29:25 -0500 Date: Wed, 9 Feb 2005 18:30:26 +0100 From: Vojtech Pavlik To: LKML , Linux-Input , Paulo Marques Subject: Re: [RFC/RFT] [patch] Elo serial touchscreen driver Message-ID: <20050209173026.GA17797@ucw.cz> References: <20050208164227.GA9790@ucw.cz> <420A0ECF.3090406@grupopie.com> <20050209170015.GC16670@ucw.cz> <20050209171438.GI10594@lug-owl.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050209171438.GI10594@lug-owl.de> User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 09, 2005 at 06:14:38PM +0100, Jan-Benedict Glaw wrote: > > I want serious support for ALL touchscreens in Linux. > > Maybe I'd write drivers for the T-Sharc and fujitsu controllers, too. > These are in a lot of POS hardware, too, and sometimes they're a pain to > use (esp. calibration). Well, if you write them, send them my way. :) > If I find a minute, I'll possibly give it a test run. I've got actual > hardware around. Thanks! > > > Also, I've already seen touchscreens where the POS manufacturer got the > > > pin-out wrong (or something like that) so the touch reports the X > > > coordinate where the Y should be, and vice-versa. I really don't know > > > where this should be handled (driver, input layer, application?), but it > > > must be handled somewhere for the applications to work. > > > > I think the best place would be in the X event driver, if X is used, or > > the graphics toolkit, and worst case the application. > > First of all, we need a really properly working Linux event driver in > XFree86/X.Org. I'm not sure if this is already the case. There is 'evtouch'. It's probably not perfect, but a good start. > > I don't believe the mirroring/flipping is kernel's job, since it tries > > to always pass the data with the least amount of transformation applied > > to achieve hardware abstraction. > > ACK. Should be handled by XFree86's driver. > > Additionally, there are two other things that need to be addressed (and > I'm willing to actually write code for this, but need input from other > parties, too:) > > - Touchscreen calibration > Basically all these touchscreens are capable of being > calibrated. It's not done with just pushing the X/Y > values the kernel receives into the Input API. These > beasts may get physically mis-calibrated and eg. report > things like (xmax - xmin) <= 20, so resolution would be > really bad and kernel reported min/max values were only > "theoretical" values, based on the protocol specs. > > I think about a simple X11 program for this. Comments? How would the program communicate with the devices? > - POS keyboards > These are real beasties. Next to LEDs and keycaps, they > can contain barcode scanners, magnetic card readers and > displays. Right now, there's no good API to pass > something as complex as "three-track magnetic stripe > data" or a whole scanned EAN barcode. Also, some > keyboards can be written to (change display contents, > switch on/off scanners, ...). We probably don't want magnetic stripe data to go through the input event stream (although it is possible to do that), so a new interface would be most likely necessary. > This is usually "solved" with a little patch that allows > userspace to write to the keyboard (/dev/psaux like), > but this is a bad hack (just look at the patches > floating around for this...). -- Vojtech Pavlik SuSE Labs, SuSE CR