Con,
is your distributed version of libusbx a vanilla version from upstream known to work fine with cgminer or you have done some local modifs to it?
I am asking because the official version of cgminer from ArchLinux community repo is built with the system libs for libusbx and jansson (was also doing it as well since I need to recompile for ADL).
Version 3.6.4 and mining with 8 AM USB Eruptors, everything is extremely stable, except when I quit the application. At that point, all threads appear to be deadlocked. I have made a manual 'kill -11' to get a core. It is not very informative as the exec was stripped. I will recompile and keep symbols to get better stacks but for the moment, I am just shooting in the water in case you know right of the bat what happens:
3.6.4 ONLY builds with the jansson and libusb included in cgminer (which is libusb-1.0.16-rc10, NOT libusbx). It ignores any installed libraries on your machine since it's the only way I can guarantee people are using the most stable libraries. As for it hanging on closing, it's a clusterfuck that I've never been able to completely fix due to millions of threads going wild and no clean way to shut it down with some things never returning. Blame me.