*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->OpenBSD man pages -> i386/pcibios (4)              



NAME    [Toc]    [Back]

     pcibios - introduction to PCI BIOS support

SYNOPSIS    [Toc]    [Back]

     pcibios0 at bios0 flags 0x0000

DESCRIPTION    [Toc]    [Back]

     OpenBSD provides support for  setting  up  PCI  controllers,
bridges, and devices
 using information extracted from the BIOS.

     Ideally, the boot firmware of a machine (a.k.a. BIOS) should
set up all
     PCI devices; assigning them I/O and memory addresses and interrupts.
     Alas,  this does not always happen, so there is some PC specific code that
     can do the initialization when OpenBSD boots.

     Flags is a bit mask each bit of which specifies a fixup procedure to
     omit.   The  following  list  specifies these procedures and
gives flags bit
     values to disable them in case they cause problems.

     0x0001  Fixup PCI I/O and memory addresses.

             Some BIOS implementations don't allocate  I/O  space
and memory
             space for all PCI devices.  Especially, a BIOS which
has "PnP OS
             mode" enabled shows this behavior.  Since  necessary
space isn't
             allocated,  those devices will not work without special handling.

             Without this flag force allocation of I/O space  and
memory space
             instead of relying upon the BIOS to do so.

             If  necessary space is already correctly assigned to
the devices,
             this option leaves the space as is.

             Although many  BIOS  implementations  leave  CardBus
bridges' space
             unallocated,   the   CardBus  bridge  device  driver
doesn't require
             this option, since the  driver  allocates  necessary
space by itself.

     0x0002   Fixup PCI bus numbering; needed for many cardbus(4)

             Each PCI bus and CardBus should have  a  unique  bus
number.  But
             some  BIOS implementations don't assign a bus number
for subordinate
 PCI buses.  And many BIOS implementations don't
assign a bus
             number for CardBuses.

             A typical symptom of this is the following boot message:
                   cardbus0 at cardslot0: bus 0 device 0...
             Please note that this cardbus0 has a bus number `0',
but normally
             the  bus  number  0 is used by the machine's primary
PCI bus.  Thus,
             this bus number for cardbus is  incorrect  (not  assigned).  In this
             situation, a device located in cardbus0 doesn't show
correct device
 ID, because its bus number 0 incorrectly refers
to the primary
 PCI bus, and a device ID in the primary PCI bus
is shown in
             the boot message instead of the device's ID  in  the

             Without  this  flag  force assignment of bus numbers
for all subordinate
 PCI buses and CardBuses.

             Since this procedure renumbers  all  PCI  buses  and
CardBuses, all
             bus  numbers  of  subordinate buses become different
when this option
 is enabled.

     0x0004  Fixup PCI interrupt routing.

             Some BIOS implementations don't assign an  interrupt
for some devices.

             This procedure assigns an interrupt for such devices
instead of
             relying upon the BIOS to do so.

             If the BIOS has already assigned an interrupt  to  a
device, this
             procedure leaves the interrupt as is.

     0x0008   Make  PCI interrupt routing fixup work with unknown
             routers.  If this flag is specified and a PCI interrupt routing
             table entry indicates that only one IRQ is available
for the entry,
 the IRQ is assumed to be already  connected  to
the device,
             and  the  corresponding  PCI Interrupt Configuration
Register will
             be configured accordingly.

             Without this flag, if a PCI interrupt router is  not
known, interrupt
 configuration will not be modified.

     0x0010   Be verbose when performing pcibios tasks.  Included
in these diagnostics
 are: PCI device address fixup tables,  interrupt fixup
             reports,  and  other  diagnostic  and non-fatal messages.

     0x0020  Make the PCI interrupt routing fixup procedure  verbose.

SEE ALSO    [Toc]    [Back]

     bios(4), intro(4), pci(4)

HISTORY    [Toc]    [Back]

     The  pcibios  code  appeared in NetBSD 1.5.  OpenBSD support
was added in
     OpenBSD 2.8.  In contrast to NetBSD  implementation  pcibios
in OpenBSD is
     a  real  device,  where  options control is done through the
flags which are
     modifiable through the boot_config(8) interface.  For OpenBSD 2.9 the PCI
     interrupt  routing establishment sequence was redone to only
fixup and
     route interrupts when attaching interrupts for a  particular
PCI device.

BUGS    [Toc]    [Back]

     The  PCIBIOS  Address Fixup option may conflict with the PCI
CardBus driver's
 own address fixup.

OpenBSD     3.6                           July      22,      2000
[ Back ]
 Similar pages
Name OS Title
pci OpenBSD introduction to PCI bus support
isa OpenBSD introduction to ISA bus support
numa_intro Tru64 Introduction to NUMA support
cardbus OpenBSD introduction to CardBus support
cbb OpenBSD introduction to CardBus support
Lithuanian Tru64 Introduction to Lithuanian language support
Portuguese Tru64 Introduction to Portuguese language support
Polish Tru64 Introduction to Polish language support
Norwegian Tru64 Introduction to Norwegian language support
hebrew Tru64 Introduction to Hebrew language support
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service