NAME    [Toc]    [Back]

     bios - a driver for PC Firmware, aka BIOS

SYNOPSIS    [Toc]    [Back]

     bios0    at mainbus0 flags 0x0000
     apm0     at bios0 flags 0x0000
     pcibios0 at bios0 flags 0x0000

DESCRIPTION    [Toc]    [Back]

     OpenBSD provides support for PC firmware, aka BIOS and  some
of its functions,
  currently:  APM  subsystem,  BIOS 32 extensions, PCI
BIOS subsystem.

     The  bios  driver  also  identifies  BIOS  type   (such   as
"AT/286+", which is
     almost  always  used in modern machines) and BIOS image date
stamp, which
     is, presumably, the day the BIOS image was compiled by  vendor and could
     be  used  as  a crude BIOS version identification.  The bios
driver also
     scans the ISA memory hole at 640K-1M for optional ROM images
and reserves
     the  space from being used by various ISA devices, for example pcic(4).

     Flags is a bit mask each bit of which specifies which  functions of the
     driver to disable.

     0x0001  BIOS 32 attachment.

             Do not probe and attach to BIOS 32 extensions, which
is one of
             the interfaces to the PCI BIOS configuration tables.

     0x0002  PCI BIOS attachment.

             Do not probe and attach the pcibios(4) device, which
performs
             certain PCI configuration tasks.

     0x0004  Do not perform the scan for ROM images  in  the  ISA
memory hole
             (0xc0000 - 0xf0000 physical addresses).

SEE ALSO    [Toc]    [Back]

     apm(4), intro(4), pcibios(4), pcmcia(4)

HISTORY    [Toc]    [Back]

     The bios driver appeared in OpenBSD 2.2.

BUGS    [Toc]    [Back]

     On  some  machines  optional ROM images do not pass checksum
check, but it's
     considered better to reserve space for those anyway,  choosing lesser evil
     from many.

OpenBSD      3.6                        February     28,     2001