I don't have the knowledge to implement this by myself, but this certainly is an interesting feature. A few years ago there was an effort to add multiplayer in a fork of gpSP, but as far as I know, nothing came out of it. Maybe one distant day I'll sit down, learn GBA, and give it a try.


Strangely it works without sudo for me.


Finally I've got some free time for Maemo, but I had to send my laptop for repairs. However, I've managed to borrow another one for a while and do some work on the accelerometer. I am not sure if flipped axes and arbitrary buttons are worth the effort, so I've implemented only basic configurability for now.

This is the changelog for gpspm 3.1.6:

• Allow D-pad diagonals to cancel each other out.
• Fixed accelerometer input in portrait mode.
• More sophisticated accelerometer handling.
• Configurable accelerometer options.

...and the GUI:

• Added accelerometer calibration dialog.

With diagonals canceling each other out, it is possible to bind only the diagonal directions to keyboard keys (e.g. A, S, Z, X) and still have full control. This might come useful in games with a lot of D-pad spinning (e.g. later levels of Kuru Kuru Kururin).

There are a few changes behind "more sophisticated accelerometer handling":

• The deadzone is radial, which means it takes the same amount of tilt to trigger a diagonal direction as a main direction.
• Uniform direction areas make it possible to trigger a diagonal direction without triggering one of main directions first.
  
• All three acceleration vectors are taken into account during calculations to determine the real tilt rather than just an approximation along X and Y axes. Thanks to that it is possible to set the neutral pitch to 90 degrees, and another advantage is that the deadzone is not deformed at steeper angles. Unfortunately, there's also a possible downside to this approach: roll is measured relative to the ground rather than the device. However, uniform direction areas compensate it to some extent and perfect motion controls in every orientation are not possible without a gyro sensor anyway.