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PCICONF(8)		FreeBSD	System Manager's Manual		    PCICONF(8)

     pciconf --	diagnostic utility for the PCI bus

     pciconf -l	[-cv]
     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, some of the func-
     tions are 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
     following format:

     foo0@pci0:0:4:0: class=0x010000 card=0x00000000 chip=0x000f1000 rev=0x01 hdr=0x00
     bar0@pci0:0:5:0: class=0x000100 card=0x00000000 chip=0x88c15333 rev=0x00 hdr=0x00
     none0@pci0:0:6:0: class=0x020000 card=0x00000000 chip=0x802910ec rev=0x00 hdr=0x00

     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 ques-
     tion, 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 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.
     Note that it will be 0 for	older cards.  The field	consists of the	card
     ID	in the upper half and the card vendor ID in the	lower half of the

     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 include 0 for most devices, 1 for PCI to PCI	bridges, and 2 for PCI
     to	CardBus	bridges.  If the most significant bit of the header type reg-
     ister is set for function 0 of a PCI device, it is	a multi-function
     device, which contains several (similar or	independent) functions on one

     If	the -c option is supplied, pciconf will	list any capabilities sup-
     ported by each device.  Each capability will be enumerated	via a line in
     the following format:

	 cap 10[40] = PCI-Express 1 root port

     The first value after the ``cap'' prefix is the capability	ID in hexadec-
     imal.  The	second value in	the square brackets is the offset of the capa-
     bility in config space in hexadecimal.  The format	of the text after the
     equals sign is capability-specific.

     If	the -v option is supplied, pciconf will	attempt	to load	the ven-
     dor/device	information database, and print	vendor,	device,	class and sub-
     class identification strings for each device.

     All invocations of	pciconf	except for -l require a	selector of the	form
     pcidomain:bus:device:function, pcibus:device:function, or pcibus:device.
     In	case of	an abrigded form, omitted selector components are assumed to
     be	0.  An optional	leading	device name followed by	@ and an optional
     final colon will be ignored; this is so that the first column in the out-
     put of pciconf -l can be used without modification.  All numbers are base

     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.

     ioctl(2), devinfo(8), kldload(8)

     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 underly-
     ing ioctl(2).

     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	7.1		       November	27, 2007		   FreeBSD 7.1


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