Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754064AbaFXOBG (ORCPT ); Tue, 24 Jun 2014 10:01:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51117 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752539AbaFXOBD (ORCPT ); Tue, 24 Jun 2014 10:01:03 -0400 Date: Tue, 24 Jun 2014 10:00:49 -0400 From: Benjamin Tissoires To: Ping Cheng Cc: Dmitry Torokhov , Jason Gerecke , linux-input , "linux-kernel@vger.kernel.org" , linuxwacom-devel Subject: Re: [PATCH 1/5] Input - wacom: create a separate input device for pads Message-ID: <20140624140049.GB7841@mail.corp.redhat.com> References: <1403557039-1487-1-git-send-email-benjamin.tissoires@redhat.com> <1403557039-1487-2-git-send-email-benjamin.tissoires@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ping, On Jun 23 2014 or thereabouts, Ping Cheng wrote: > Hi Benjamin, > > On Mon, Jun 23, 2014 at 1:57 PM, Benjamin Tissoires > wrote: > > Currently, the pad events are sent through the stylus input device > > for the Intuos/Cintiqs, and through the touch input device for the > > Bamboos. > > > > To differentiate the buttons pressed on the pad from the ones pressed > > on the stylus, the Intuos/Cintiq uses MISC_SERIAL and ABS_MISC. This > > lead to a multiplexing of the events into one device, which are then > > splitted out in xf86-input-wacom. Bamboos are not using MISC events > > because the pad is attached to the touch interface, and only BTN_TOUCH > > is used for the finger (and DOUBLE_TAP, etc...). However, the user space > > driver still splits out the pad from the touch interface in the same > > way it does for the pro line devices. > > > > The other problem we can see with this fact is that some of the Intuos > > and Cintiq have a wheel, and the effective range of the reported values > > is [0..71]. Unfortunately, the airbrush stylus also sends wheel events > > (there is a small wheel on it), but in the range [0..1023]. From the user > > space point of view it is kind of difficult to understand that because > > the wheel on the pad are quite common, while the airbrush tool is not. > > > > A solution to fix all of these problems is to split out the pad device > > from the stylus/touch. This decision makes more sense because the pad is > > not linked to the absolute position of the finger or pen, and usually, the > > events from the pad are filtered out by the compositor, which then convert > > them into actions or keyboard shortcuts. > > This is a very good solution. I like it. > > > For backward compatibility with current xf86-input-wacom, the pad devices > > still present the ABS_X, ABS_Y and ABS_MISC events, but they can be > > completely ignored in the new implementation. > > I do not think we need to keep ABS_X and ABS_Y for pad. We've already > supported a tablet (Intuos pen small, a pen only tablet with buttons > reported on touch interface) that does not set ABS_X and ABS_Y for > pad. Hmm, actually, when I tried removing X and Y, xf86-input-wacom complained that max_x and max_y where set to 0, and it thus rejected the device. Maybe there is a special quirk in the xorg driver for the device you mentioned? Anyway, it's not a big deal, and when both xorg and libinput will know how to handle properly the pad device nodes, we can remove this. > > Unless you plan to use other means to tell userland those events are > from PAD tool, ABS_MISC is necessary and is a reasonable way to group Well, given that the pad now has its own input node, ABS_MISC could be dropped. We just need to teach the users that whichever event comes from this input device is a PAD event. > PAD events. So, I do not think it is for backward compatibility. It is > there to stay. With that said, the whole patchset is > > > Signed-off-by: Benjamin Tissoires > > Reviewed-by: Ping Cheng > Thanks, that is greatly appreciated! > Thank you, Benjamin, for your support. > > Ping > Cheers, Benjamin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/