More on splbio()

[briggs_(_at_)_puma_(_dot_)_macbsd_(_dot_)_com]

[ Context: I'm trying to get the mac68k to boot with an ncr53c96 using
  a customized esp driver.  It's getting hung up trying to mount root
  because it's getting SCSI transactions w/o SCSI_POLL, but where the
  kernel is basically polling (
	s = splbio();
	while (!done)
		tsleep();
	splx(s);
  where "done" is waiting for xs->flags &ITS_DONE or the equivalent for
  the buf in biowait()).  splbio blocks the disk interrupts and since
  SCSI_POLL wasn't specified, it is in a state where it needs an
  interrupt to continue.  ]

OK.  As was pointed out to me, the sleep/tsleep will normally cause
someone else to be scheduled.  In mountroot(), though, there is just
proc0 so nothing else will ever get scheduled, and the processor stays
at splbio, preventing me from getting the required interrupt.  Can't we
still end up with all processes waiting on I/O, so all are running at
splbio and the driver is still waiting on an interrupt which it can't
receive?

I must still be being dense...  I don't see how the sparc port works
right now...  Can someone please give me some enlightenment?

Thanks,
-allen

-- 
              Allen Briggs - end killing - briggs_(_at_)_macbsd_(_dot_)_com