setpci(8) The PCI Utilities setpci(8)
setpci – configure PCI devices
setpci [options] devices operations…
setpci is a utility for querying and configuring PCI devices.
All numbers are entered in hexadecimal notation.
Root privileges are necessary for almost all operations, excluding
reads of the standard header of the configuration space on some operat‐
ing systems. Please see lspci(8) for details on access rights.
-v Tells setpci to be verbose and display detailed information
about configuration space accesses.
-f Tells setpci not to complain when there’s nothing to do (when no
devices are selected). This option is intended for use in
widely-distributed configuration scripts where it’s uncertain
whether the device in question is present in the machine or not.
-D `Demo mode’ — don’t write anything to the configuration regis‐
ters. It’s useful to try setpci -vD to verify that your complex
sequence of setpci operations does what you think it should do.
Show setpci version. This option should be used stand-alone.
–help Show detailed help on available options. This option should be
Show a list of all known PCI registers and capabilities. This
option should be used stand-alone.
PCI access options
The PCI utilities use the PCI library to talk to PCI devices (see
pcilib(7) for details). You can use the following options to influence
The library supports a variety of methods to access the PCI
hardware. By default, it uses the first access method avail‐
able, but you can use this option to override this decision. See
-A help for a list of available methods and their descriptions.
The behavior of the library is controlled by several named
parameters. This option allows to set the value of any of the
parameters. Use -O help for a list of known parameters and their
-H1 Use direct hardware access via Intel configuration mechanism 1.
(This is a shorthand for -A intel-conf1.)
-H2 Use direct hardware access via Intel configuration mechanism 2.
(This is a shorthand for -A intel-conf2.)
-G Increase debug level of the library.
Before each sequence of operations you need to select which devices you
wish that operation to affect.
machine has several host bridges, they can either share a common
bus number space or each of them can address a PCI domain of its
own; domains are numbered from 0 to ffff), bus (0 to ff), slot
(0 to 1f) and function (0 to 7). Each component of the device
address can be omitted or set to “*”, both meaning “any value”.
All numbers are hexadecimal. E.g., “0:” means all devices on
bus 0, “0” means all functions of device 0 on any bus, “0.3”
selects third function of device 0 on all buses and “.4” matches
only the fourth function of each device.
are given in hexadecimal and may be omitted or given as “*”,
both meaning “any value”.
When -s and -d are combined, only devices that match both criteria are
selected. When multiple options of the same kind are specified, the
rightmost one overrides the others.
There are two kinds of operations: reads and writes. To read a regis‐
ter, just specify its name. Writes have the form name=value,value…
where each value is either a hexadecimal number or an expression of
type data:mask where both data and mask are hexadecimal numbers. In the
latter case, only the bits corresponding to binary ones in the mask are
changed (technically, this is a read-modify-write operation).
There are several ways how to identity a register:
· Tell its address in hexadecimal.
· Spell its name. Setpci knows the names of all registers in the
standard configuration headers. Use `setpci –dumpregs’ to get
the complete list. See PCI bus specifications for the precise
meaning of these registers or consult header.h or
/usr/include/pci/pci.h for a brief sketch.
· If the register is a part of a PCI capability, you can specify
the name of the capability to get the address of its first reg‐
ister. See the names starting with `CAP_’ or `ECAP_’ in the
· If the name of the capability is not known to setpci, you can
refer to it by its number in the form CAPid or ECAPid, where id
is the numeric identifier of the capability in hexadecimal.
· Each of the previous formats can be followed by +offset to add
an offset (a hex number) to the address. This feature can be
useful for addressing of registers living within a capability,
or to modify parts of standard registers.
· Finally, you should append a width specifier .B, .W, or .L to
choose how many bytes (1, 2, or 4) should be transferred. The
width can be omitted if you are referring to a register by its
name and the width of the register is well known.
All names of registers and width specifiers are case-insensitive.
asks for the word-sized command register.
4.w is a numeric address of the same register.
asks for a 32-bit word starting at the location of the command
register, i.e., the command and status registers together.
specifies the upper byte of the vendor ID register (remember,
PCI is little-endian).
corresponds to the second word of the power management capabil‐
asks for the first 32-bit word of the extended capability with
The PCI Utilities are maintained by Martin Mares
pciutils-3.3.1 09 April 2015 setpci(8)