[BRLTTY] Filter keyboard keypresses on Linux

[Mario Lang]

Dave Mielke <dave at mielke.cc> writes:

> How should we decide which event device is the keyboard? The simplest might be 
> someting like selecting the first device which can deliver some well-known key 
> event, e.g. space or enter. Any better ideas?

Yes, select the keyboard based on the bindings the user configured.
I.e., if I have a binding for KEY_HELP, it does not make
sense to select a keyboard without that key.

> What about systems with more than one keyboard?

I think the approach above would eliminate most race conditions with
several keyboards.  Ideally, brltty could grab all keyboards
that have the keys the user wants to use.

> Does anyone know what happens if the same event device is opened more than 
> once, which could happen, for example, if more than one brltty is started?

I *think* if the application does not "grab" the keyboard,
other apps can still open the device.  I never tested
what happens if a grabbed keyboard gets opened a second time,
but that should be fairly easy to test with a custom piece of C code.
I am currently swamped with work, so I could look at this
case on the weekend at the earliest.

-- 
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