flag and a callback function which gets called whenever a target is
selected on a channel.
The macppc wdc driver needs to reprogram its timing register
differently for each target on a channel each time that target is
selected. I also changed the ATA4_TIME_TO_TICK to use a divisor of
15, which brings our timing calculations consistent with darwin.
These patches fix problems on my dual usb ibook with combo dvd/cdrw
drive because the hard drive supports udma and the combo drive does
not. Without turning off the udma timings in the configuration
register, I cannot access the non-udma combo drive.
f629228e87