PCHB(4) FreeBSD Kernel Interfaces 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.
Support is provided for the following devices:
i450 PCIset (Orion)
Supports additional PCI buses.
Reliance Computer ROSB4, CNB20HE, CNB20LE
Supports additional PCI buses.
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, most PCI devices of class Bridge and sub-class
Bridge Host are supported just as PCI attachment points. A few other
system control devices not listed here are supported by pchb.
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 <
[email protected]>.
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).
FreeBSD 14.1-RELEASE-p8 July 16, 2013 FreeBSD 14.1-RELEASE-p8