The
wdc driver provides the interface with the hardware for the
ata(4) driver. This driver supports IDE and EIDE controllers, as well as MFM, RLL and ESDI on the ISA bus. PCI IDE controllers in legacy mode are also supported, but the
pciide(4) driver may provide more functionality.
On the ISA front-end, the following flags are supported:
0x0001
Enables 32-bit I/O negotiation in the driver. This is known to cause problems with some motherboards.
0x0002
Don't probe for the second drive.
0x0004
Set WDC_CAPABILITY_ATA_NOSTREAM flag.
0x0008
Set WDC_CAPABILITY_ATAPI_NOSTREAM flag.