Hi!..
Uhm yes, I guess stop_this_cpu() does exactly what the name implies :-)Undoubtedly -- perhaps the called CPU halts, and therefore cannot reply. :)The second bug, is that for the halt case at least,I'm guessing there's a reason it doesn't pass '1' as the last argument,
nobody waits for the other CPU to actually halt
before continuing.. so we sometimes enter the shutdown
code while other CPUs are still active.
This causes some machines to hang at shutdown,
unless CPU_HOTPLUG is configured and takes them offline
before we get here.
because that would fix that issue?
But some kind of pre-halt ack, perhaps plus a short delay by the callerSomething like this will close the window to right up until the point
after receipt of the ack, would probably suffice to kill that bug.
But I really haven't studied this code enough to know,
other than that it historically has been a sticky area
to poke around in.
where the other CPUs have 'almost' called halt().
Now I took a look at context... why not simply use same trick swsusp
uses, and do a hot unplug of all cpus at the end of shutdown?