1.\" $OpenBSD: pchb.4,v 1.13 2004/03/21 19:50:44 miod Exp $ 2.\" 3.\" Michael Shalayeff, 2000. Public Domain. 4.\" 5.Dd April 12, 2000 6.Dt PCHB 4 7.Os 8.Sh NAME 9.Nm pchb 10.Nd PCI-Host Bridge 11.Sh SYNOPSIS 12.Cd "pchb* at pci? dev ? function?" 13.Cd "pci* at pchb?" 14.Sh DESCRIPTION 15The 16.Nm 17driver provides support for PCI-Host adapter-specific functions for 18the following devices: 19.Pp 20.Bl -tag -width Ds -offset indent -compact 21.It i450 PCIset (Orion) 22Supports additional PCI busses. 23.It Reliance Computer ROSB4, CNB20HE, CNB20LE 24Supports additional PCI busses. 25.It i82424ZX (Saturn) 26Disables CPU-PCI write posting. 27.It i82443BX 28Provides workaround for the following errata: 29"An incorrect address may be driven on the 30DRAM bus, resulting in memory data being 31fetched from the wrong location." 32.It i82810/810E, i82815/815E, i82820, i82840 33Supports the random numbers generator, 34supplying random bytes from the system's thermal noise. 35Driven by periodic checks for available data from the generator, 36it supplies entropy to the 37.Xr random 4 38driver for common usage. 39.El 40.Pp 41On amd64 and i386 systems all other PCI devices of class 42.Nm Bridge 43and sub-class 44.Nm Bridge Host 45are supported just as PCI attachment points. 46.Pp 47The macppc port supports several Apple and Motorola bridges. 48.Sh SEE ALSO 49.Xr intro 4 , 50.Xr pci 4 , 51.Xr random 4 52.Sh HISTORY 53Random number generator support first appeared in 54.Ox 2.7 . 55.Sh AUTHORS 56Support for true RNG present on i82810 chips was added by 57.An Michael Shalayeff Aq mickey@openbsd.org . 58.Sh BUGS 59Real RNG probe should fix the PCI scanning loop so it would find the Firmware 60Hub (i82802) which actually contains the RNG device and 61probe it as a real PCI device (i.e., common PCI registers are there). 62