setpci(8) — Linux manual page


setpci(8)                     The PCI Utilities                    setpci(8)

NAME         top

       setpci - configure PCI devices

SYNOPSIS         top

       setpci [options] devices operations...

DESCRIPTION         top

       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
       operating systems.  Please see lspci(8) for details on access rights.

OPTIONS         top

   General options
       -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

       -D     `Demo mode' -- don't write anything to the configuration
              registers.  It's useful to try setpci -vD to verify that your
              complex sequence of setpci operations does what you think it
              should do.

       -r     Avoids bus scan if each operation selects a specific device
              (uses the -s selector with specific domain, bus, slot, and
              function). This is faster, but if the device does not exist,
              it fails instead of matching an empty set of devices.

              Show setpci version. This option should be used stand-alone.

       --help Show detailed help on available options. This option should be
              used stand-alone.

              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 its behavior:

       -A <method>
              The library supports a variety of methods to access the PCI
              hardware.  By default, it uses the first access method
              available, but you can use this option to override this
              decision. See -A help for a list of available methods and
              their descriptions.

       -O <param>=<value>
              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 default values.

       -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.

       -s [[[[<domain>]:]<bus>]:][<slot>][.[<func>]]
              Consider only devices in the specified domain (in case your
              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

       -d [<vendor>]:[<device>]
              Select devices with specified vendor and device ID. Both ID's
              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.

OPERATIONS         top

       There are two kinds of operations: reads and writes. To read a
       register, 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
              register. See the names starting with `CAP_' or `ECAP_' in the
              --dumpregs output.

       ·      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.

       ·      To choose how many bytes (1, 2, or 4) should be transferred,
              you should append a width specifier .B, .W, or .L. The width
              can be omitted if you are referring to a register by its name
              and the width of the register is well known.

       ·      Finally, if a capability exists multiple times you can choose
              which one to target using @number. Indexing starts at 0.

       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

              asks for the first 32-bit word of the extended capability with
              ID 0x108.

SEE ALSO         top

       lspci(8), pcilib(7)

AUTHOR         top

       The PCI Utilities are maintained by Martin Mares <>.

COLOPHON         top

       This page is part of the pciutils (PCI utilities) project.
       Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this
       manual page, send it to  This page was
       obtained from the project's upstream Git repository
       ⟨git://⟩ on
       2020-07-14.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-06-06.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
       there is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

pciutils-3.6.4                 25 January 2020                     setpci(8)

Pages that refer to this page: proc(5)procfs(5)pcilib(7)lspci(8)update-pciids(8)