SC(4) FreeBSD Kernel Interfaces Manual SC(4)
NAME
sc - Sun Sun-2 SCSI bus host adaptor driver
SYNOPSIS
sun2
sc0 at mbmem0 addr 0x80000 ipl 2
sc1 at mbmem0 addr 0x84000 ipl 2
sun2 and sun4
sc0 at vme0 addr 0x200000 irq 2 vec 0x40
DESCRIPTION
The sc driver provides support for the Sun Microsystems "Sun-2" SCSI Bus
Controller chipset found on various VME boards (Sun part #s 501-1045,
501-1138, 501-1149, and 501-1167) and on the "Sun-2 SCSI/Serial" (Sun
part # 501-1006) Multibus board.
All versions of this driver can be configured with a flags directive in
the config(1) file. The values are bits in a bitfield, and are
interpreted as follows:
0x0ff Set bit (1<<target) to disable SCSI parity checking
0x100 Set this bit to disable DMA interrupts (poll)
0x200 Set this bit to disable DMA entirely (use PIO)
For example: "flags 0x1ff" would disable DMA interrupts, and disable
parity checking for targets 0-7. The "target" is the SCSI ID number of a
particular device on a particular SCSI bus.
SEE ALSO
cd(4), ch(4), intro(4), scsi(4), sd(4), st(4)
AUTHORS
Matt Fredette <
[email protected]>,
David Jones,
Gordon Ross <
[email protected]>,
Adam Glass <
[email protected]>,
Jason R. Thorpe <
[email protected]>.
BUGS
This SCSI chipset is rumored to have bugs in its handling of SCSI parity,
therefore it is recommended that you disable parity on all SCSI devices
connected to this controller, and configure it with a 0x0ff value for its
flags directive in the config(1) file.
This chipset has no support for raising the ATN signal, so there is no
way to ever schedule a MSG_OUT phase on the bus. Currently, the driver
will ultimately reset the bus if this phase is ever requested by the
upper layer SCSI driver.
This chipset has no support for SCSI disconnect/reselect. This means
that slow devices, such as tape drives, can hog, or "lock up" the SCSI
bus.
This driver has not been tested in combination with non-SCSI devices
behind Emulex or Adaptec bridges, which are common in Sun 2s and in Sun
Shoebox-type configurations. These devices pre-date the SCSI-I spec, and
might not behave the way the chipset code currently expects.
FreeBSD 14.1-RELEASE-p8 June 28, 2001 FreeBSD 14.1-RELEASE-p8