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Re: [Qemu-devel] [PULL v2 8/9] input-linux: refine mouse detection
From: |
Gerd Hoffmann |
Subject: |
Re: [Qemu-devel] [PULL v2 8/9] input-linux: refine mouse detection |
Date: |
Thu, 14 Apr 2016 10:07:15 +0200 |
On Do, 2016-04-14 at 09:42 +0200, Ladi Prosek wrote:
> On Wed, Apr 13, 2016 at 5:45 PM, Gerd Hoffmann <address@hidden> 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
- [Qemu-devel] [PULL v2 0/9] virtio-input; live migration support, various bugfixes, Gerd Hoffmann, 2016/04/13
- [Qemu-devel] [PULL v2 7/9] virtio-input: fix emulated tablet axis ranges, Gerd Hoffmann, 2016/04/13
- [Qemu-devel] [PULL v2 9/9] virtio-input: support absolute axis config in pass-through, Gerd Hoffmann, 2016/04/13
- [Qemu-devel] [PULL v2 6/9] virtio-input: add live migration support, Gerd Hoffmann, 2016/04/13
- [Qemu-devel] [PULL v2 2/9] move const_le{16, 23} to qemu/bswap.h, add comment, Gerd Hoffmann, 2016/04/13
- [Qemu-devel] [PULL v2 1/9] virtio-input: add parenthesis to const_le{16, 32}, Gerd Hoffmann, 2016/04/13
- [Qemu-devel] [PULL v2 3/9] virtio-input: add missing key mappings, Gerd Hoffmann, 2016/04/13
- [Qemu-devel] [PULL v2 8/9] input-linux: refine mouse detection, Gerd Hoffmann, 2016/04/13
- [Qemu-devel] [PULL v2 5/9] virtio-input: implement pass-through evdev writes, Gerd Hoffmann, 2016/04/13
- [Qemu-devel] [PULL v2 4/9] virtio-input: retrieve EV_LED host config bits, Gerd Hoffmann, 2016/04/13
- Re: [Qemu-devel] [PULL v2 0/9] virtio-input; live migration support, various bugfixes, Peter Maydell, 2016/04/14