On Sun, 17 Nov 2002, Robert Watson wrote: > I've seen several reports that using a serial break to get into ddb is now > quite a bit more reliable than a keyboard break. If you're not already
This is a fact. In RELENG_4, the keyboard interrupt handler is a normal tty interrupt handler so it can't interrupt things blocked by spltty(), while the sio interrupt handler is a fast interrupt handler so it can interrupt almost anything (anything not blocked by disable_intr(), which should be everything except fast interrupt handlers and the entry code for normal interrupt handlers). Things are much more broken in -current: the keyboard interrupt handler is non-MPSAFE so it can't interrupt things blocked by Giant (which is most syscalls), and the sio interrupt handler is a "fast" interrupt handler so it can't interrupt things blocked by critical_enter() (which is too many things for too long, so fast interrupt handlers aren't actually fast). Bruce To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-current" in the body of the message
