Input device design
krahn at niehs.nih.gov
Thu Aug 25 11:45:02 PDT 2005
Russell Shaw wrote:
> > 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 X
> > driver support. Something like UPnP is needed, but UPnP is overly
> > complex for simple input device purposes, and still incomplete. Also, MS
> > has a patent for device communication via XML. I was thinking of a
> > trivial UPnP-like protocol using ConciseXML. ConciseXML is less verbose,
> > 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.
> IMHO, it's a crappy idea to use verbose textual xml for communication
> protocols. It's best for what it was designed: inter-application
> of data, such as between word processors. Internal to an application
> like X,
> a fast and compact (maybe even binary) purpose-built protocol optimized for
> the application should be used.
> Also, X should stay scaleable to small embedded devices, which precludes
> throwing in gobs of xml parsers. Gtk going to xml to configure menus peeved
> me off no-end:(
Jim Getty's suggested XML, with the argument that input-event data is
small enough that the overhead/waste is minimal. I'm suggesting
ConciseXML because it's less overly-verbose than 'real' XML.
A binary alternative could probably be based on this:
IRIX uses a shared-memory queue to feed event data to X. Maybe some
ideas could be gotten from looking at IRIX.
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