If we ever come across a really memoryless device it should not be
particularly difficult to add another callback to ff-memless-next which
would emulate conditional effects with constant force.

It should be noted that some (/many?) applications/games already use the
CF with position feedback to emulate behaviour such as springs. The feed
back loop is simply not fast enough to do emulation of friction/inertia.

I don't believe that the FF layer in the kernel should be 'tricked out'
with lots of emulation features.

As a game designer (ok... tinkerer) it's a bit of a pain that devices lie
about what they can really do - ie. gamepads claiming periodic ability
when all they are doing is faking it with rumble.

Simon.