NCR(4)                    OpenBSD Programmer's Manual                   NCR(4)

NAME
     ncr - NCR/Symbios 53C8xx SCSI driver

SYNOPSIS
     ncr* at pci? dev ? function ?
     scsibus* at ncr?

     option FAILSAFE
     option NCR_CDROM_ASYNC
     option NCR_IOMAPPED
     option NCR_TEKRAM_EEPROM
     option NCR_VERBOSE=integer
     option SCSI_NCR_DFLT_TAGS=integer
     option SCSI_NCR_MAX_SYNC=integer
     option SCSI_NCR_MAX_WIDE=integer
     option SCSI_NCR_SYMBIOS_COMPAT
     option SCSI_NCR_TRUST_BIOS

DESCRIPTION
     The ncr driver provides support for the NCR (now Symbios) 53C810, 53C815,
     53C820, 53C825, 53C860, 53C875, 53C876, 53C885, 53C895, 53C896, 53C1510,
     and 53C1510D SCSI controller chips.

     ncr has been replaced by the siop driver.

     The following kernel configuration options are available:

     option FAILSAFE
     Disables tagged command queuing and forces asynchronous transfers for CD-
     ROM devices.

     option NCR_CDROM_ASYNC
     Always use asynchronous transfers with CD-ROM devices.  By default, syn-
     chronous transfers are used if the CD-ROM supports it.

     option NCR_IOMAPPED
     Attempt to access the controller chip via I/O port-mapped I/O, falling
     back to memory-mapped I/O if the I/O ports couldn't be mapped.  By de-
     fault, memory-mapped I/O is tried first.

     option NCR_TEKRAM_EEPROM
     Enables support for reading the configuration EEPROM of the Tekram DC-390
     series of SCSI cards.  Enable this only if using a Tekram DC-390 card.

     option NCR_VERBOSE=integer
     Specifies the verbosity of driver messages during a kernel boot.  A value
     of 1 will provide extra information about the controller's capabilities
     and setup.  A value of 2 or greater will print information about the con-
     troller's registers.

     option SCSI_NCR_DFLT_TAGS=integer
     Specifies the maximum number of tags per logical unit.  Unless FAILSAFE
     is defined, the default value is 4.  A value of 0 will disable tagged
     command queuing.

     option SCSI_NCR_MAX_SYNC=integer
     Specifies the maximum synchronous transfer frequency to use, in kHz.  A
     value of 0 means asynchronous transfers only.  The default is 25000
     (25MHz), but the actual value used depends on the type of controller chip
     and what its maximum transfer rate is.  For controllers supporting fast
     transfers only, this is 10000 (10MHz).  If wide transfers are supported,


     the value is 20000 (20MHz).

     option SCSI_NCR_MAX_WIDE=integer
     Specifies the maximum SCSI bus width, with 0 meaning 8 bits and 1 meaning
     16 bits.  Defaults to 1 on chips that support wide SCSI, 0 otherwise.
     Set this to 0 to disable wide transfers even if both controller and de-
     vice support them (e.g. when using a wide controller and wide drive
     through a narrow cable).

     option SCSI_NCR_SYMBIOS_COMPAT
     Enables the use of the GPIO register as a disk activity indicator.  En-
     able this if the activity LED isn't working, but make sure the card
     doesn't use GPIO for something else.  Cards known to support this: ASUS
     SC875, Diamond FirePort 40, and Symbios SYM8751S.

     option SCSI_NCR_TRUST_BIOS
     Specifies that the driver should use the register configuration set by
     the firmware instead of configuring the chip itself.

BUGS
     Some Quantum drives (specifically the Atlas series) return ``queue full''
     responses when a very small number of tags is used which can confuse the
     driver.  With such drives, you can use

     option  SCSI_NCR_DFLT_TAGS=0

     in your kernel configuration file to disable tagged command queuing.

SEE ALSO
     cd(4), ch(4), intro(4), scsi(4), sd(4), siop(4), st(4), uk(4)

OpenBSD 2.9                     March 24, 2000                               2
