Input device design

Johnson, Charles F charles.f.johnson at
Thu Aug 25 11:22:58 PDT 2005

Some of us folks at Intel are very interested is problem of input device
auto configuration.  There was some discussions on the list in early
Aug/late July regarding this.  (See:

While I can't promise anything, we looking at putting some real
resources on this.  In particular, we're interested in something similar
to your second paragraph.  (A system service to input devices.)

--Charles Johnson
Intel Corporation
charles.f.johnson at

>-----Original Message-----
>From: xorg-bounces at [mailto:xorg-
>bounces at] On Behalf Of Joe Krahn
>Sent: Thursday, August 25, 2005 10:38 AM
>To: Discuss issues related to the xorg tree
>Subject: Input device design
>I have over the last several years made efforts to work with XInput,
>never had sufficient knowledge of the X server internal design goals,
>and have been waiting for a LONG time for this to the top of Jim
>work pile.
>I've written some of my ideas to
>It seemed the interest has been too low. Maybe it's finally time to get
>Questions and more ideas:
>Are people in favor of implementing the traditional core devices as
>permanent virtual devices, with one or more real devices sending core
>events through the virtual devices? The virtual pointer would always be
>absolute, screen-resolution, and update with RandR.
>There needs to be a system service that tracks available input devices.
>Should there also be an X client device manager that maps in those
>devices, sort of like a Window Manager? This would allow for user-prefs
>of devices names, sensitivities, etc.
>It is a good idea to avoid using the system level combined
>device /dev/input/mice, and let multiple devices be seen as multiple
>devices by X. The X client can then decide if a newly plugged in device
>should be accepted as a core-input device.
>There's been a lot of discussion on how to map specific input devices.
>don't think the X server should have to think about USB HUB routes,
>etc., to define a device. Input devices management should be a bit more
>like IP address / routing management. Devices get a name, possibly a
>generic DHCP-like name, and things like X that want to actually use
>should require minimal knowledge of the hardware. Good/Bad?
>There also needs to be a generic client/server protocol for input
>devices, which can be used to connect remote devices, emulate devices,
>or provide a way to connect new hardware that does not yet have proper
>driver support. Something like UPnP is needed, but UPnP is overly
>complex for simple input device purposes, and still incomplete. Also,
>has a patent for device communication via XML. I was thinking of a
>trivial UPnP-like protocol using ConciseXML. ConciseXML is less
>and is IMHO a better fit to data than is regular XML, plus helps avoid
>conflicts with the UPnP people and/or the MS patent.
>Joe Krahn
>xorg mailing list
>xorg at

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