Radeon Open Source Drivers

[dscharrer]

It's been working fine on a Radeon 7750 in Xubuntu 15.10 x64 for me.

Worked for you since day number one, or it started working some time latter?

It works since day one with the radeonsi driver (Radeon HD 7750 or higher) but afaik there has been no progress for the r600g driver (used for older hardware).

Since this seems to only affect one driver for one hardware vendor it is most likely a driver issue and needs to be fixed there. The best Frictional can do here (besides contributing to the driver themselves, which is unreasonable) is to make sure that the right driver developers have a copy of the game. Your best bet is to follow and perhaps add your information to this bug report: https://bugs.freedesktop.org/show_bug.cgi?id=92229