NAME    [Toc]    [Back]

     pchb - PCI-Host Bridge

SYNOPSIS    [Toc]    [Back]

     pchb* at pci? dev ? function?
     pci* at pchb?

DESCRIPTION    [Toc]    [Back]

     The pchb driver provides support for  PCI-Host  adapter-specific functions
     for the following devices:

           i450 PCIset (Orion)
                   Supports additional PCI busses.
           Reliance Computer ROSB4, CNB20HE, CNB20LE
                   Supports additional PCI busses.
           i82424ZX (Saturn)
                   Disables CPU-PCI write posting.
           i82443BX
                   Provides  workaround for the following errata:
"An incorrect
                   address may be driven on the DRAM bus, resulting in memory
                   data being fetched from the wrong location."
           i82810/810E, i82815/815E, i82820, i82840
                   Supports the random numbers generator, supplying random
                   bytes from the system's thermal noise.  Driven
by periodic
                   checks  for available data from the generator,
it supplies
                   entropy to the random(4) driver for common usage.

     On  amd64  and  i386  systems all other PCI devices of class
Bridge and subclass
 Bridge Host  are  supported  just  as  PCI  attachment
points.

     The macppc port supports several Apple and Motorola bridges.

SEE ALSO    [Toc]    [Back]

     intro(4), pci(4), random(4)

HISTORY    [Toc]    [Back]

     Random number generator support first  appeared  in  OpenBSD
2.7.

AUTHORS    [Toc]    [Back]

     Support  for  true  RNG present on i82810 chips was added by
Michael
     Shalayeff <[email protected]>.

BUGS    [Toc]    [Back]

     Real RNG probe should fix the PCI scanning loop so it  would
find the
     Firmware Hub (i82802) which actually contains the RNG device
and probe it
     as a real PCI device (i.e., common PCI registers are there).

OpenBSD      3.6                          April      12,     2000