1.\" $OpenBSD: bios.4,v 1.11 2007/05/31 19:19:54 jmc Exp $ 2.\" 3.\" Copyright (c) 2001 Michael Shalayeff 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF MIND, 21.\" USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" 26.Dd $Mdocdate: May 31 2007 $ 27.Dt BIOS 4 i386 28.Os 29.Sh NAME 30.Nm bios 31.Nd a driver for PC Firmware, aka BIOS 32.Sh SYNOPSIS 33.Cd "bios0 at mainbus0 flags 0x0000" 34.Cd "apm0 at bios0 flags 0x0000" 35.Cd "pcibios0 at bios0 flags 0x0000" 36.Sh DESCRIPTION 37.Ox 38provides support for PC firmware, aka BIOS and some of its functions, 39currently: APM subsystem, BIOS32 extensions, PCI BIOS subsystem. 40.Pp 41The 42.Nm 43driver also identifies BIOS type (such as "AT/286+", which is 44almost always used in modern machines) and BIOS image date stamp, 45which is, presumably, the day the BIOS image was compiled by vendor 46and could be used as a crude BIOS version identification. 47The 48.Nm 49driver also scans the ISA memory hole at 640K-1M for optional 50ROM images and reserves the space from being used by various 51ISA devices, for example 52.Xr pcic 4 . 53.Pp 54Flags is a bit mask, each bit of which specifies which functions 55of the driver to disable. 56.Bl -tag -width 0x0001 57.It 0x0001 58BIOS32 attachment. 59.Pp 60Do not probe or attach to BIOS32 extensions. 61BIOS32 is one of 62the interfaces to the PCI BIOS configuration tables. 63.It 0x0002 64PCI BIOS attachment. 65.Pp 66Do not probe or attach the 67.Xr pcibios 4 68device, which performs certain PCI configuration tasks. 69.It 0x0004 70Do not perform the scan for ROM images in the ISA memory hole 71(0xc0000 - 0xf0000 physical addresses). 72.It 0x0008 73SMBIOS attachment. 74.Pp 75Do not probe or attach to SMBIOS. 76SMBIOS provides greater detail about system hardware configuration 77and is required to attach 78.Xr ipmi 4 79on most systems. 80.El 81.Sh SEE ALSO 82.Xr apm 4 , 83.Xr intro 4 , 84.Xr pcibios 4 , 85.Xr pcmcia 4 86.Sh HISTORY 87The 88.Nm 89driver 90appeared in 91.Ox 2.2 . 92.Sh BUGS 93On some machines optional ROM images do not pass checksum check, 94but it's considered better to reserve space for those anyway, 95choosing lesser evil from many. 96