From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mauro Carvalho Chehab Subject: Re: [v3,1/4] input: add an EV_REL event for high-res vertical wheel Date: Fri, 7 Apr 2017 10:32:14 -0300 Message-ID: <20170407103214.64b3eb07@vento.lan> References: <20170407121751.GA13764@mail.corp.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from ec2-52-27-115-49.us-west-2.compute.amazonaws.com ([52.27.115.49]:48685 "EHLO osg.samsung.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755455AbdDGNcW (ORCPT ); Fri, 7 Apr 2017 09:32:22 -0400 In-Reply-To: <20170407121751.GA13764@mail.corp.redhat.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Benjamin Tissoires Cc: linux-input@vger.kernel.org, Dmitry Torokhov , Jonathan Corbet , Peter Hutterer , Hans Verkuil , Ping Cheng , Kamil Debski , Douglas Anderson , linux-doc@vger.kernel.org Em Fri, 7 Apr 2017 14:17:51 +0200 Benjamin Tissoires escreveu: > Hi Mauro, > > On Apr 07 2017 or thereabouts, Mauro Carvalho Chehab wrote: > > As some devices can produce either low-res or high-res > > vertical wheel EV_REL events, add a new event to allow > > userspace to distinguish between them. > > > > Signed-off-by: Mauro Carvalho Chehab > > --- > > Documentation/input/event-codes.rst | 16 +++++++++++++--- > > include/uapi/linux/input-event-codes.h | 1 + > > 2 files changed, 14 insertions(+), 3 deletions(-) > > > > diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst > > index 92db50954169..0c8591d39bc6 100644 > > --- a/Documentation/input/event-codes.rst > > +++ b/Documentation/input/event-codes.rst > > @@ -185,10 +185,20 @@ instead of EV_REL codes. > > > > A few EV_REL codes have special meanings: > > > > -* REL_WHEEL, REL_HWHEEL: > > +* REL_WHEEL: > > > > - - These codes are used for vertical and horizontal scroll wheels, > > - respectively. > > + - These codes are used for vertical scroll wheels. > > + > > + - REL_WHEEL is for normal wheel operational mode, e. g. low-resolution > > + (line-based) scroll. > > + > > + - REL_HIRES_WHEEL should be used when the wheel has two resolutions and it > > + is in high-resolution mode, e. g. the same angular movement that would > > + produce a single REL_WHEEL will produce multiple REL_HIRES_WHEEL events. > > + > > +* REL_HWHEEL: > > + > > + - This code is used for horizontal scroll wheels. > > > > EV_ABS > > ------ > > diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h > > index 3af60ee69053..23b2d377af59 100644 > > --- a/include/uapi/linux/input-event-codes.h > > +++ b/include/uapi/linux/input-event-codes.h > > @@ -703,6 +703,7 @@ > > #define REL_DIAL 0x07 > > #define REL_WHEEL 0x08 > > #define REL_MISC 0x09 > > +#define REL_HIRES_WHEEL 0x0a > > There is one issue here. The HID input layer has a tendency to map > usages to REL_MISC +1, +2, +3, etc... When it doesn't know how to map an > usage, the core layer maps it to the next one. > > I am not aware of devices exposing such REL axes, but I wouldn't be > surprised if the issue will not raise at some point. > > We already had an issue with ABS events where ABS_MISC are conflicting > with ABS_MT_SLOTS. Luckily, we have a little empty space between > ABS_MISC and ABS_MT_SLOT, which allows userspace to detect such issues. > > Could you give the define a bigger number (and maybe reserve a couple of > REL_MISC-n) to make sure that we do not end up with joysticks exporting > REL_HIRES_WHEEL? Sure. How many REL_MISC-n should be reserved? > I'll try the rest of the series on the MX Master today. It would be great if you could test it! Regards, Mauro