Aaugh! xinput not working for drag lock!

[Tom Horsley]

On Sat, 1 Aug 2015 09:06:30 -0400
Tom Horsley wrote:

> on fedora 22 I don't get drag lock (although
> I do get the top left mouse button mapped to
> button 8).
> 
> Anyone have any idea what might have changed here?

Well, isn't that clever. X isn't using "evdev" any longer.
It is using the "totally compatible" drop in replacement
"libinput" in fedora 22. Naturally, it has no support
for drag lock. Just as naturally, the xinput "lisp-props"
command still shows me the drag lock property as one
I can set. After spending all weekend figuring this
out, I have discovered a simple command that fixes
all my problems:

dnf erase xorg-x11-drv-libinput

Now X finds and uses the nasty old useless obsolete
evdev input driver and I can finally use my trackball
again.