---
name: "pcitweak"
section: "1x"
platform: "linux"
package: "xutils"
version: "4.3.0.dfsg.1-14sarge7"
release: "Debian 3.1 (Sarge)"
platforms: ["linux"]
url: "https://new.carta.tech/pcitweak"
---

# pcitweak(1x)

read/write PCI config space

## NAME

pcitweak - read/write PCI config space

## SYNOPSIS

**pcitweak** **-l**\
 **pcitweak** **-r** *PCI-ID* \[**-b**\|**-h**\] *offset*\
 **pcitweak** **-w** *PCI-ID* \[**-b**\|**-h**\] *offset* *value*

## DESCRIPTION

*Pcitweak* is a utility that can be used to examine or change registers in the PCI configuration space.  On most platforms *pcitweak* can only be run by the root user.

## OPTIONS

- **-l**

  Probe the PCI buses and print a line for each detected device.  Each line contains the bus location (bus:device:function), chip vendor/device, card (subsystem) vendor/card, revision, class and header type.  All values printed are in hexadecimal.

- **-r** *PCI-ID*

  Read the PCI configuration space register at *offset* for the PCI device at bus location *PCI-ID*. *PCI-ID* should be given in the form bus:device:function, with each value in hexadecimal.  By default, a 32-bit register is read.

- **-w** *PCI-ID*

  Write *value* to the PCI configuration space register at *offset* for the PCI device at bus location *PCI-ID*. *PCI-ID* should be given in the form bus:device:function, with each value in hexadecimal.  By default, a 32-bit register is written.

- **-b**

  Read or write an 8-bit value (byte).

- **-h**

  Read or write a 16-bit value (halfword).

## SEE ALSO

[scanpci(1)](/scanpci/1.md)

## AUTHORS

David Dawes (*dawes@xfree86.org*).