During the boot sequence, the esp driver searches the linked list for LUN info by LUN ID. At this point the driver will attach on that instance, and then attempt to attach every sub-device.
There are at least 4 variations of the configuration 3 register. A second config register must be loaded to inquire the chip revision, otherwise the ncr53c9x_reset function will not set the defaults correctly.
The drive attach routine attempts to set the appropriate bit to put the chip into Fast SCSI mode so that it does not have to be figured out each time. This will then be stored in the NCR registers for later use.
The esp driver makes use of the LSI 64854 DMA engine which contains three independent channels designed to interface with an NCR539X SCSI controller; an AM7990 Ethernet controller; and certain types of parallel port hardware. As such this driver may eventually replace the amd(4) driver for network hardware.
The following driver specific error messages may be reported: