This may appear to be "out of the blue" comment, but interestingly enough
the same kernel in conjunction with the PAM/rlimits solution really sucks on
a macbook pro. Namely, anything below 512 x 3 with RT privileges is a lesson
in futility. I don't think that the realtime-lsm will fare any better as
running stuff as root makes no difference whatsoever. Ultimately, I am
hoping that this is because of a potentially incomplete hw/chipset support
(there are a few non-volatile errors during the boot sequence but probably
mostly due to GPT/MBR clash). Otherwise, MBPs may prove to be fancy
room-heaters/doorstops when it comes to Linux audio...
Ico