On Do, 2016-04-14 at 09:42 +0200, Ladi Prosek wrote: > On Wed, Apr 13, 2016 at 5:45 PM, Gerd Hoffmann <kra...@redhat.com> wrote: > > Read absolute and relative axis information, only classify > > devices as mouse/tablet in case the x axis is present. > > I, too, had to come up with a heuristic to classify input devices in > my guest driver and what I ended up with is different. > > For example my Dell keyboard has two endpoints, one with a bunch of > keys and LEDs, so it would be classified as a keyboard. The second one > with special keys (KEY_MUTE, KEY_WWW, KEY_BACK, ..) *and* with a mouse > (REL_X, REL_Y, REL_WHEEL, BTN_LEFT, ...). The reason for this are the > zoom in/out buttons. Pressing them generates Ctrl down on the first > endpoint and mouse wheel up/down on the second one. Releasing them > then translates to Ctrl up. Crazy.
So they are building os-specific hotkeys into the hardware. Crazy indeed. It's not obvious though why the second function has keyboard keys. Possibly they want the first function look like a pretty standard keyboard without any extra fluff, to sidestep compatibility issues with old software not expecting that. > So I wouldn't use exclusive OR when classifying because there are > combo devices out there. Maybe anything with an EV_KEY (minus BTN_*) > would be a keyboard? Right now each device type has its own callback function, we have to reorganize that to support a device being classified as both mouse and keyboard. Worth considering, but not 2.6 material. There surely is more room for improvements, not only in input-linux but in the input system in general and in the virtual input devices, for example to support all those extra keys on multimedia keyboards. cheers, Gerd
