PCHB(4) OpenBSD Programmer's Manual PCHB(4)
NAME
pchb - PCI-Host Bridge
SYNOPSIS
pchb* at pci?
pci* at pchb?
DESCRIPTION
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 sub-
class Bridge Host are supported just as PCI attachment points.
The macppc port supports several Apple and Motorola bridges.
SEE ALSO
intro(4), pci(4), random(4)
HISTORY
Random number generator support first appeared in OpenBSD 2.7.
AUTHORS
Support for true RNG present on i82810 chips was added by Michael
Shalayeff <mickey@openbsd.org>.
BUGS
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 4.0 April 12, 2000 1