[PATCH] Add configuration option for use of SIGIO handlers for input events

[Peter Hutterer]

On Tue, Oct 06, 2009 at 03:22:02PM +0100, Nix wrote:
> On 13 Sep 2009, Peter Hutterer spake thusly:
> > I still see configurations with AllowEmptyInput off because there was a
> > brief period when that fixed a certain broken setup. Now people use it
> > because they read it somewhere and thought it's a good idea.
> 
> Actually I use it because with it off my keyboard is ignored unless HAL
> is running, even as of X.org 1.6.x, and HAL is an unreliable POS which
> failed to start for *years* for me, so I am reluctant to rely on it for
> anything.
> 
> It's not all cargo-culting, unless you consider 'keyboard doesn't work,
> turn this option on and now it does' to be cargo-culting.

This is exactly the thing I was referring to in my previous email. Your
configuration is wrong, it dates back to some period where this actually
fixed some bug. The only reason why it works in your case is because HAL -
even if running - is not set up correctly.

When you have AEI off, the server will require a CorePointer and
CoreKeyboard device in the config (and create default devices if not found).
The same devices will then be added thanks to HAL, resulting in duplicate
button presses and triple key presses*.

If you don't want to use HAL that's fine with me, the correct option to
disable it is 'AutoAddDevices "off"' though. Just turning AEI off causes
issues when HAL works correctly.

Cheers,
  Peter

* incidentally, the same thing will happen once we have udev support instead
of HAL.