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

   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 not.

       -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

       -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 device.

       -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.

       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.

       lspci(8), pcilib(7)

       The PCI Utilities are maintained by Martin Mares <>.

pciutils-3.7.0                    31 May 2020                        setpci(8)