pciconf -- diagnostic utility for the PCI bus
pciconf -l [-v]
pciconf -a selector
pciconf -r [-b | -h] selector addr[:addr2]
pciconf -w [-b | -h] selector addr value
The pciconf utility provides a command line interface to functionality
provided by the pci(4) ioctl(2) interface. As such, it is only available
to users with write access to /dev/pci, normally only the super-user.
With the -l option, it lists all devices found by the boot probe in the
foo0@pci0:4:0: class=0x010000 card=0x00000000 chip=0x000f1000 rev=0x01 hdr=0x00
bar0@pci0:5:0: class=0x000100 card=0x00000000 chip=0x88c15333 rev=0x00 hdr=0x00
none0@pci0:6:0: class=0x020000 card=0x00000000 chip=0x802910ec rev=0x00 hdr=0x00
If the -v option is supplied, pciconf will attempt to load the vendor/device
information database, and print vendor, device, class and subclass
identification strings for each device.
The first column gives the device name, unit number, and selector. If
there is no device configured in the kernel for the PCI device in question,
the device name will be ``none''. Unit numbers for unconfigured
devices start at zero and are incremented for each unconfigured device
that is encountered. The selector is 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 subclass
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.
All invocations of pciconf except for -l 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
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 addr of
device selector and prints out its value in hexadecimal. The optional
second address addr2 specifies a range to read. The -w option writes the
value into a configuration space register at byte offset addr 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
The PCI vendor/device information database is normally read from
/usr/share/misc/pci_vendors. This path can be overridden by setting the
environment variable PCICONF_VENDOR_DATABASE.
The pciconf utility appeared first in FreeBSD 2.2. The -a option was
added for PCI KLD support in FreeBSD 3.0.
The pciconf utility was written by Stefan Esser and Garrett Wollman.
The -b and -h options are implemented in pciconf, but not in the underlying
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 kldload to provide the
device with a driver KLD, and reading of configuration space registers
may cause a failure in badly designed PCI chips.
FreeBSD 5.2.1 February 7, 1997 FreeBSD 5.2.1 [ Back ]