PCICONF(8)

NAME
pciconf - diagnostic utility for the PCI bus

SYNOPSIS
pciconf -l
pciconf -a selector
pciconf -r selector [-b | -h] reg
pciconf -w selector [-b | -h] reg value

DESCRIPTION
The pciconf command provides a command line interface to the functionality provided by /dev/pci's ioctl(2) interface. With the -l option, it lists all devices found by the boot probe in the following format:

    pci0:4:0: class=0x010000 card=0x00000000 chip=0x000f1000 rev=0x01 hdr=0x00
    pci0:5:0: class=0x000100 card=0x00000000 chip=0x88c15333 rev=0x00 hdr=0x00
    pci0:6:0: class=0x020000 card=0x00000000 chip=0x802910ec rev=0x00 hdr=0x00

The first column gives the selector in a form which may directly be used for the other forms of the command. The second column is the class code, with the class byte printed as two hex digits, followed by the sub-class and the interface bytes. The third column gives the contents of the subvendorid register, introduced in revision 2.1 of the PCI standard. It is 0 for most current (2.0) PCI cards, but is supposed to be loaded with a unique card identification code in newly developed PCI cards. The field consists of the card ID in the upper half and the card vendor ID in the lower half of the value.

The fourth column contains the chip device ID, which identifies the chip this card is based on. It consists of two fields, identifying the chip and its vendor, as above. The fifth column prints the chip's revision. The sixth column describes the header type. Currently assigned header types are 0 for all devices except PCI to PCI bridges, and 1 for such bridge chips. If the most significant bit of the header type register is set for function 0 of a PCI device, it is a multi-function device, which contains several (similar or independent) functions on one chip.

The -l option is the only one available to non-root users. All other invocations of pciconf require a selector of the form pcibus:device (optionally followed by :function). A final colon may be appended and will be ignored; this is so that the first column in the output of pciconf -l can be used without modification. All numbers are base 10.

With the -a flag, pciconf determines whether any driver has been assigned to the device identified by selector. An exit status of zero indicates that the device has a driver; non-zero indicates that it does not.

The -r option reads a configuration space register at byte offset reg of device selector and prints out its value in hexadecimal. The -w option writes the value into a configuration space register at byte offset reg of device selector. For both operations, the flags -b and -h select the width of the operation; -b indicates a byte operation, and -h indicates a halfword (two-byte) operation. The default is to read or write a longword (four bytes).

SEE ALSO
ioctl(2), modload(8)

HISTORY
The pciconf command appeared first in FreeBSD 2.2. The -a option was added for PCI LKM support in FreeBSD 3.0.

AUTHORS
The pciconf facility was written by Stefan Esser and Garrett Wollman.

BUGS
The -b and -h options are implemented in pciconf, but not in the underlying ioctl().

It might be useful to give non-root users access to the -a and -r options. But only root will be able to execute a modload to provide the device with a driver LKM, and reading of configuration space registers may cause a failure in badly designed PCI chips.