Re: [PATCH v3] Documentation: Add evdev type and code definitions

[Peter Hutterer]

On Thu, Mar 24, 2011 at 10:50:23PM -0700, Dmitry Torokhov wrote:
> On Fri, Mar 25, 2011 at 10:36:02AM +1000, Peter Hutterer wrote:
> > On Thu, Mar 24, 2011 at 03:45:51PM -0400, Chase Douglas wrote:
> > > On 03/24/2011 02:44 PM, Chris Bagwell wrote:
> > > > Looking good.  Minor comments at end.
> > > > 
> > > > On Thu, Mar 24, 2011 at 12:44 PM, Chase Douglas
> > > > <chase.douglas@xxxxxxxxxxxxx> wrote:
> > > >> +Touchscreens:
> > > >> +----------
> > > >> +ABS_{X,Y} must be reported with the location of the touch. BTN_TOUCH must be
> > > >> +used to report when a touch is active on the screen.
> > > >> +BTN_{MOUSE,LEFT,MIDDLE,RIGHT} must not be reported. BTN_TOOL_<name> events
> > > >> +should be reported where possible.
> > > > 
> > > > Does the real button event restriction solve something?  I know
> > > > majority of touchscreens are not sending a button today but usually
> > > > there is a button on the touchscreen frame that I'd image at least
> > > > some devices hooking it up to touchscreen interface.
> > > >
> > > > stylus+touchscreen combo devices are surely going to want to do this.
> > > 
> > > Perhaps this should be more clearly for touchscreen-only devices (not
> > > tablets or a mix). The problem we end up seeing is drivers who use
> > > BTN_LEFT because they want a touch to generate a primary button press in
> > > X. I want to prevent people from doing this.
> > 
> > suggest that they use BTN_0 instead then?
> > 
> 
> Umm, I'd hope X evdev driver could handle BTN_TOUCH without
> BTN_LEFT/BTN_0 to indicate primary button. Legacy mode (mousedev)
> already translateds BTN_TOUCH/BTN_LEFT/BTN_0 into "left PS/2 button".

evdev treats BTN_TOUCH as button, yes. my comment above refers to additional
buttons on the tablet that aren't touch. maybe I misread the above though.

Cheers,
  Peter
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