I was trying to find a way to fix this warning on my Thinkpad. I have
found out that it is normal for this to happen and can safely be ignored.
Reference links:
https://bbs.archlinux.org/viewtopic.php?id=153205
https://unix.stackexchange.com/questions/249654/message-at-shutdown-watchdog-did-not-stop
However, if I set reboot-acpi AND irqpoll (in GRUB_CMDLINE_LINUX in
/etc/default/grub) on a ThinkPad T61 (my computer), I get this error:
"CPU pipe B FIFO underrun"
So naturally I don't set reboot-acpi! :) (I was experimenting in trying
to get rid of the watchdog warnings but gave up as it seems harmless and
won't go away anyway).
Just thought I'd share this in case others run into these things.
