Of course the reboot wiped any logs we could have used for clues as to what happened. Next time it'll be good to preserve this info. I suspect the local subnet went down.
P.S. for some reason the system logs are priveleged now - I ran sudo sysctl kernel.dmesg_restrict=0 on c1psl to make it readable by any user. This change won't persist on reboot.
I restarted the IOC but it didn't help.
I am now rebooting c1psl... That seemed to help. PMC screen seem to be working again. I am able to lock the PMC now.