On 31.05.2012, Darryl L. Pierce wrote:
At this point I have to power down the
old Irish way by holding the power button.
I don't know if the Fedora kernels are compiled with m-sysrq support,
but you could try to set "kernel.sysctl = 1" in /etc/sysctl.conf,
followed by a "sysctl -p". Next time your system hangs, press
AltGr+PrtScr, hold them down and start slowly pressing "r", "e" and
"i".
R gives you control over the keyboard, E sends a SIGTERM to all
processes, and if this doesn't help, I sends SIGKILL, and your machine
should proceed to shut down. If it doesn't, you can at least sync your
disks by pressing "S", "U"nmount and "R"eboot if
neccessary.