Re: master 3b41141708: Expose the name of an event's input device to Lisp

[Po Lu]

Brian Cully <bjc@spork.org> writes:

> At least on Linux, that’s a monotonically increasing counter, and old
> device addresses aren’t reused until you wrap the counter.

That's not true on X.  This is implementation dependent, but the X.Org
server will always try to reuse a device ID that is currently available.

Device ID order is what's used when you try to enumerate all devices on
the X server with a QueryDevice request, so for our purposes it's
"enumeration order".

That only makes "device enumeration order" even more confusing.

>       I’m not sure how the device naming system in various GUIs reacts
> to having multiple, identical devices attached, but a conservative guess
> would be that they’re disambiguated by enumeration order, in which case
> even the device name isn’t stable in the presence of identical devices
> coming and going.

That's only a last resort.  On X Windows, the input driver is supposed
to take care of that using serial numbers and any other information that
might serve to identify a device uniquely.