.\" Copyright (c) 1996 Berkeley Software Design, Inc.
.\" All rights reserved.
.\" The Berkeley Software Design Inc. software License Agreement specifies
.\" the terms and conditions for redistribution.
.Dd June 6, 1996
.Dt DPT 4 i386
.Os
.Sh NAME
.Nm dpt
.Nd
.Tn Driver for DPT
SCSI host bus adapters including the PM3021, PM3222, PM3224 SmartRAID SCSI
RAID adapters
.Sh SYNOPSIS
.Cd "dpt0 at isa?"
.Cd "dpt0 at isa? port ? drq 5"
.Cd "dpt0 at eisa?"
.Cd "dpt0 at pci?"
.Cd "tg* at dpt?"
.Sh DESCRIPTION
The
.Nm dpt
driver provides access to SCSI disks and disk arrays controlled by DPT host
bus adapters and SmartRAID SCSI RAID adapters through the standard SCSI disk
.Xr sd 4
interface. 
ISA, EISA and PCI adapter versions
are supported. Single or mulitple channel adapters and hardware based RAID
arrays are supported.  Software RAID (RAID drives spanning adapters) is
not supported.
.Pp
The DPT ISA adapters use jumpers or BIOS configuration options to alter 
the I/O address,
interrupt level (IRQ) and DMA channel (DRQ) used by the adapter.
The I/O address of an adapter may be one of 0x1F0, 0x170, 0x330 or 0x230
and this is the order in which adapters will be found during 
autoconfiguration.
Other addresses are not allowed.
The IRQ of an adapter may be one of 15, 14 or 12.
The DRQ of an adapter may be one of 5, 6 or 7.
The I/O address, IRQ and DRQ qualifiers in the system configuration file
are optional however if specified, only adapters which exactly match the 
qualifiers will be found.
Adapters with system configuration file entries which do not specify a DRQ 
will be probed during autoconfiguration without using DMA.
A 16-bit ISA slot is required when specifying a DRQ.
.Pp
The DPT EISA and PCI adapters automatically configure using the configuration
mechanism of the bus they are on. For the EISA adapters the EISA configuration
utility must be run to set the IRQ and let the system BIOS know that there is
a card present. With PCI adapters the IRQ sometimes has to be assigned from
a BIOS configuration menu (some BIOS's do this automatically).
.Pp
DPT adapters which support wide SCSI or multiple SCSI channels are a special
case and require some additions to the configuration file.
These adapters use the concept of a "pseudo host bus adapter" to work
around addressing limitations in the driver.
In the wide SCSI case, all narrow targets (target IDs < 8) appear as
targets of the real adapter. However all wide targets appear as targets of 
a pseudo-adapter which appears as the
next adapter described in the configuration file. For example, a PM3224W
is configured with one narrow SCSI disk drive as target 0 and one wide 
SCSI disk drive as target 8.
The config entry looks like this:
.sp
.Cd dpt0 at pci ?
.Cd dpt1 at pci ?
.sp
The narrow SCSI drive shows up as target 0 of adapter dpt0. 
The wide SCSI drive shows up as target 0 of dpt1. Note that dpt1 does
not physically exist.
Enough entries in the system configuration file must be created to satisfy ALL
real and pseudo adapters which might be created during autoconfiguration.
Adapters which support multiple SCSI buses behave similarly. A separate
pseudo-adapter is created for each additional SCSI bus.
.Pp
Note that buses which have no targets either because no targets are connected
or because those targets are powered off will not be found during
autoconfiguration. In the case of adapters which support wide SCSI or 
multiple SCSI buses throught the use of "pseudo" adapters,
this can lead to an unexpected numbering of adapters which
will undoubtedly cause grief. It is strongly suggested, therefore, that
all targets be connected and powered up before autoconfiguration takes
place.
.Pp
All DPT host bus adapters must be configured before they can be used
with any operating system. Please contact DPT directly to obtain the
latest information on configuration utilities for DPT adapters.
Note that in the absence of a native BSD/OS version of the dptmgr
configuration utility the DOS version may be used (under DOS) to configure
DPT adapters which will then later be used by BSD/OS. However please
be aware that the DOS version may allow the creation of configurations,
like software RAIDs, which are not supported by BSD/OS.
.Sh DIAGNOSTICS
The following diagnostics may be printed during autoconfiguration:
.Bl -diag
.It 
dpt0: probe failed - hardcoded IRQ doesn't match config data (irq 5)
.sp
An adapter specified in the system configuration file was found but the
IRQ reported by the adapter did not match the IRQ in the system
configuration file.
Resolve the conflict between the jumpers on the adapter and the value
specified in the system configuration file.
.It 
dpt0: probe failed - hardcoded DRQ (drq 7) doesn't match config data (drq 5)
.sp
An adapter specified in the system configuration file was found but the
DRQ reported by the adapter did not match the DRQ in the system
configuration file.
Resolve the conflict between the jumpers on the adapter and the value
specified in the system configuration file.
.El
.Sh SEE ALSO
.Xr sd 4 ,
.Sh HISTORY
The
.Nm dpt
driver first appeared as a patch to BSD/OS 2.1.