with this little patch, i'm now unable to generate overruns.  and
i'm pushing this machine *very* hard at the moment... it is a
headless SS2 with a modem on ttyb.  i used to get 1-5 overruns
with mycroft's new driver, at fairly regularly intervals, where
the number of overruns would increase somewhat closely to how the
load on the machine did.  now, with the load as high as it's been,
i'm not seeing any problems.  infact, in some cases, from `systat
vmstat 1', i'm seeing almost 6000 lev12 interrupts a second, and
over 10000 interrupts total, a second, at times.  it seems to
average out at about 4000 and 8500.


thank you chuck!