On Mon, Dec 30, 2013 at 12:44:21PM +0100, David Herrmann wrote: > Hi > > On Mon, Dec 30, 2013 at 12:20 PM, Antonio Ospite > <ospite@xxxxxxxxxxxxxxxxx> wrote: > > On Sun, 29 Dec 2013 16:52:09 -0800 > > Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> wrote: > > > >> Hi Antonio, > >> > >> On Mon, Dec 23, 2013 at 05:17:43PM +0100, Antonio Ospite wrote: > >> > Model this part of the API after the Sony PlayStation 3 Controller which > >> > exposes independent analog values for each one of the D-Pad buttons. > >> > > >> > The PS3 programming API psl1ght also maps the analog D-Pad buttons > >> > individually. > >> > >> Hmm, even though the hardware is capable of producing independent analog > >> values does are they really useful? Looking at my PS3 controller I do > >> not think users will be pressing up/down and left/right dpad buttons at > >> the same time. > >> > > > > I must agree it's unlikely, while still possible. > > > >> I'd rather keep using ABS_HAT0X/Y unless there is really good reason for > >> introducing new events. > >> > > > > Having analog D-Pad values reported independently was proposed for these > > reasons: > > > > - it matches _some_ existing hardware closely (that was the main > > reason TBH, to simplify the drivers); > > > > - it happens to follow what it's being done for D-Pad digital buttons, > > they are also reported independently. > > > > However if some other hardware reported D-Pad axis combined already > > then I agree that using something like ABS_HAT0X/Y is safer, I see > > decomposing HORIZ/VERT into the separate LEFT/RIGHT and UP/DOWN to be > > less intuitive (not harder tho). > > > > Another doubt: David, in the other email you mentioned we could use > > ABS_DPAD_HORIZ/VERT, any particular reason to introduce them in place > > of ABS_HAT0X/Y? > > A "HAT" is an axis on the top of a joystick, nothing else. It seems > troublesome to overload the definition (which we did for many years). > Device-detection based on advertised ABS-bits gets pretty hard if we > reuse ABS-bits for different hardware. The most annoying example of > what happens is accelerometers being misdetected by Xorg as > mouse-input because they reuse ABS_X/Y. But they are good as joysticks (also ABS_X/ABS_Y). I do not think having all unique events for all device types is feasible. Can we provide hints (via properties) to lessen ambiguity, like we do with direct/indirect pointers for touchscreens/tablets? Thanks. -- 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
