On Tue, Mar 09, 2010 at 07:32:57PM -0500, Rafi Rubin wrote: > On 03/09/2010 06:42 PM, Dmitry Torokhov wrote: > >On Tue, Mar 09, 2010 at 06:38:22PM -0500, Rafi Rubin wrote: > >>On 03/09/2010 06:23 PM, Henrik Rydberg wrote: > >>>Rafi Rubin wrote: > >>>>>Single touch should be goverened by one of BTN_TOUCH or ABS_PRESSURE. > >>>>>BTN_TOOL_DOUBLETAP is a two-finger event. > >>>> > >>>>That definitely makes sense to me. I really don't know why wacom uses > >>>>double tap there. > >>>> > >>>>Is there any harm in letting through the BTN_0 events? Is the "rdesc" > >>>>mapping defined by the hardware or hid? > >>> > >>>I cannot imagine BTN_0 will do any harm. In synaptics, the BTN_X buttons are > >>>mapped to multibuttons without clear-cut usage. The button events that carry > >>>well-defined semantic meaning with regard to touch screens are BTN_TOUCH (any > >>>finger), BTN_TOOL_FINGER (one finger), BTN_TOOL_PEN (pen), BTN_TOOL_DOUBLETAP > >>>(two fingers) and BTN_TOOL_TRIPLETAP (three fingers or more). > >>> > >>>Henrik > >>> > >> > >>Perhaps we should have a general touch device document. > >> > >>I looked at the evdev code. And as you say for single touch > >>devices, BTN_TOUCH is the bit that matters. It only broken because > >>I pulled the TOUCH<- 0 when I removed BTN_0. > >> > >>So why does evdev associate BTN_TOOL_FINGER with touchpads > >>(resulting in the wrong set of assumptions and a poorly calibrated > >>touch screen)? I suppose that's really a discussion for another > >>list. > >> > > > >Historic reasons. When Synaptics driver was in works we needed an event > >that is different from BTN_TOUCH to differentiate from touchscreens. > > So should I clear the BTN_TOOL_FINGER bit for ntrig, or push to > clean up evdev? > > At the moment nothing is actually expecting or emitting the finger > events. Given the move to actual mt support does it make sense to > use finger, double and triple for single touch events? I'd vote for > letting the user space mt tools handle more advanced button clicks. > I'd opt for this as well; let's leave BTN_TOOL_FINGER to touchpads. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
