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

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:

quoted

On Thu, Mar 24, 2011 at 03:45:51PM -0400, Chase Douglas wrote:

quoted

On 03/24/2011 02:44 PM, Chris Bagwell wrote:

quoted

Looking good.  Minor comments at end.

On Thu, Mar 24, 2011 at 12:44 PM, Chase Douglas
[off-list ref] wrote:

quoted

+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