setpci

setpci [options] [devices] [operations]

-s [[domain:]bus:]device[.func]
    Selects the target PCI device by its address in the format [[domain:]bus:]device[.func]. This is the most common way to specify a device.

-d [vendor]:[device]
    Selects devices by matching their PCI Vendor ID and/or Device ID.

-P class
    Selects devices belonging to a specified PCI class code.

-v
    Enables verbose output, showing more details about operations.

offset.size=value[/mask]
    Performs a write operation to a register. offset is the hexadecimal register address. size is B (byte), W (word), or L (long word). value is the hexadecimal data to write. An optional mask can be used for bitwise operations.

offset.size
    Performs a read operation from a register. offset is the hexadecimal register address. size is B (byte), W (word), or L (long word).

--dumpregs
    Dumps all known PCI configuration registers for the selected devices.

setpci is a powerful command-line utility used for querying and configuring PCI device configuration registers directly. It allows users to read and write arbitrary bytes, words, or long words in a PCI device's configuration space. This tool is invaluable for low-level hardware debugging, performance tuning, and specific device initialization tasks that go beyond standard driver capabilities.

Due to its direct interaction with hardware registers, setpci requires root privileges. Incorrect usage can lead to system instability, crashes, or data corruption, as it bypasses the operating system's normal hardware abstraction layers. Users typically need a good understanding of PCI architecture and device-specific register layouts (often found in datasheets) to use it effectively and safely.

Requires root privileges to execute. Incorrect use can lead to system instability, crashes, data loss, or render hardware unusable until a reboot. Users should possess a thorough understanding of PCI architecture and device-specific register functions before attempting to modify values. Always back up critical data before performing low-level hardware manipulations.

Due to its ability to directly manipulate hardware settings, setpci poses a significant security risk if used by unauthorized users. It can potentially be exploited to bypass security measures, cause denial-of-service, or introduce vulnerabilities. Access to this command should be strictly limited to trusted system administrators or developers.

setpci is part of the pciutils package, a collection of utilities for Linux that inspect and manipulate PCI devices. Developed and maintained over many years, it has become a standard component in the Linux ecosystem for low-level PCI device management and debugging. Its development closely tracks changes in PCI specifications and hardware advancements, ensuring compatibility and functionality across a wide range of devices.

lspci(8), pcilib(7), update-pciids(8)