NAME
bios —
a driver for PC Firmware, aka
BIOS
SYNOPSIS
bios0 at mainbus0 flags 0x0000
apm0 at bios0 flags 0x0000
pcibios0 at bios0 flags 0x0000
DESCRIPTION
OpenBSD provides support for PC firmware, aka BIOS and some of its functions, currently: APM subsystem, BIOS32 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
- BIOS32 attachment.
Do not probe or attach to BIOS32 extensions. BIOS32 is one of the interfaces to the PCI BIOS configuration tables.
- 0x0002
- PCI BIOS attachment.
Do not probe or 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).
- 0x0008
- SMBIOS attachment.
Do not probe or attach to SMBIOS. SMBIOS provides greater detail about system hardware configuration and is required to attach ipmi(4) on most systems.
SEE ALSO
HISTORY
The bios driver appeared in
OpenBSD 2.2.
BUGS
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.