Manual: setpci

setpci(8) The PCI Utilities setpci(8)

NAME
setpci - configure PCI devices

SYNOPSIS
setpci [options] devices operations...

DESCRIPTION
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
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 in‐
tended 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.

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

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

--dumpregs
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
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 =
The behavior of the library is controlled by several named parameters. This option allows one 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.

DEVICE SELECTION
Before each sequence of operations you need to select which devices you wish that operation to affect.

-s [[[[]:]]:][][.[]]
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 []:[][:[:]]
Select devices with specified vendor, device, class ID, and programming interface. The ID's are given in
hexadecimal and may be omitted or given as "*", both meaning "any value". The class ID can contain "x" charac‐
ters which stand for "any digit".

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
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 to identify 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.

EXAMPLES
COMMAND
asks for the word-sized command register.

4.w is a numeric address of the same register.

COMMAND.l
asks for a 32-bit word starting at the location of the command register, i.e., the command and status regis‐
ters together.

VENDOR_ID+1.b
specifies the upper byte of the vendor ID register (remember, PCI is little-endian).

CAP_PM+2.w
corresponds to the second word of the power management capability.

ECAP108.l
asks for the first 32-bit word of the extended capability with ID 0x108.

Manual: setpci

Related Commands: