.\"
.\" Copyright (c) 1994 Jordan Hubbard
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.\" $FreeBSD: src/share/man/man4/bt.4,v 1.10.4.6 2001/10/01 13:07:23 dd Exp $
.\"
.Dd November 29, 2012
.Dt BT 4
.Os
.Sh NAME
.Nm bt
.Nd Buslogic/Mylex MultiMaster SCSI host adapter driver
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device scbus"
.Cd "device bt"
.Ed
.Sh DESCRIPTION
This driver provides access to the
.Tn SCSI
bus connected to a Buslogic/Mylex MultiMaster or compatible controller:
.Bd -ragged -offset indent
MultiMaster "W" Series Host Adapters:
.Bl -column "BT-956CD " "PCI " "Commands " "Description"
.Em "Adapter" Ta Em "Bus" Ta Em "Commands" Ta Em "Description"
BT-948	PCI	192	Ultra SCSI-3
BT-958	PCI	192	Wide Ultra SCSI-3
BT-958D	PCI	192	Wide Differential Ultra SCSI-3
.El
.Pp
MultiMaster "C" Series Host Adapters:
.Bl -column "BT-956CD " "PCI " "Commands " "Description"
.Em "Adapter" Ta Em "Bus" Ta Em "Commands" Ta Em "Description"
BT-946C	PCI	100	Fast SCSI-2
BT-956C	PCI	100	Wide Fast SCSI-2
BT-956CD	PCI	100	Wide Differential Fast SCSI-2
.El
.Ed
.Pp
AMI FastDisk Host Adapters that are true BusLogic MultiMaster clones are also
supported by this driver.
.Pp
Tagged queueing is supported on 'W' series adapters and 'C' series adapters
with firmware of rev 4.42 and higher.
.Pp
Boards with certain firmware revisions may lock up under heavy load to
certain devices, especially if tagged queueing is used.
Should you encounter
a problem with your adapter, contact Mylex technical support and ensure you
have the latest firmware for your controller.
.Sh FILES
.Bl -tag -width /usr/share/man0/template.doc -compact
.It Pa /sys/dev/disk/buslogic/bt.c
Core Driver Implementation
.It Pa /sys/dev/disk/buslogic/btreg.h
MultiMaster Register Set and Core Driver Data Structures
.It Pa /sys/dev/disk/buslogic/bt_pci.c
PCI Bus Driver Attachment
.El
.Sh SEE ALSO
.Xr cd 4 ,
.Xr da 4 ,
.Xr sa 4 ,
.Xr scsi 4
.Sh HISTORY
The
.Nm
driver first appeared in the
.Bx 386
patch kit.
.Sh AUTHORS
.An -nosplit
.An Julian Elischer
wrote a driver for the Multimaster cards that appeared in the
.Bx 386
patch kit.
The driver was rewritten by
.An Justin T. Gibbs
to take advantage of new board features and work with the CAM SCSI framework in
.Fx 3.0 .
.Pp
Special thanks to
.An Leonard N. Zubkoff
for writing such a complete and well documented Mylex/BusLogic MultiMaster
driver for Linux.
Support in this driver for the wide range of MultiMaster
controllers and firmware revisions, with their otherwise undocumented quirks,
would not have been possible without his efforts.