https://bugs.freedesktop.org/show_bug.cgi?id=72785
--- Comment #39 from Michel Dänzer michel@daenzer.net --- (In reply to Linux User from comment #36)
P.P.S. and what about better fan/intensity control?
See bug 73338.
(In reply to Linux User from comment #38)
P.S. also there is another silly issue. If I just install Ubuntu and run bfgminer on multi-GPU setup within X session, it would only see 1st GPU (where X server running). Remaining GPUs are not detected. Fix is to either run bfgminer as root (extremely unsafe!!!) or create new user and make "video" it's primary group. The user who installs Ubuntu is a member of "video" group, but "video" is his secondary group, which is very common. Somehow, kernel seems to disregard permissions in such case and would issue -EPERM on certain syscall, making bfgminer unable to find GPUs except one used by X. Generally it means that user can't use more than 1 GPU unless he is either root (very dangerous!) or video is his primary group (inconvenient and uncommon). I believe it is a bug and I should file it? Since I fail to understand how average Joe would be able to use some OpenCL program in multi-GPU setup and get it working "by default" on all available GPUs. I guess I should file it as new bug? Is it kernel issue or MESA, etc?
You should report this to Ubuntu.