- wdc_xfer to ata_xfer
- channel_queue to ata_queue
and move them to <dev/ata/atavar.h> so they can be used by non-wdc ATA
controllers. Clean up the member names of these structures while at it.
most polling.
2) Clean up some goofiness in pciide -- get rid of the whole "candisable" path
(it's gratuitous) and simplify the code by calling pciide_map_compat_intr(),
*_set_modes() and wdc_print_modes() from central locations.
3) Add a register writability and register ghost test to eliminate phantom
drives more quickly.
caveats, but works quite well in a lot of MP cases, and all
UP cases that I have tested. Parts of this will hopefully be
reworked in the not-too-distant future.