Linus Torvalds 570f7e331f Merge tag 'pci-v7.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci
Pull PCI updates from Bjorn Helgaas:
 "Resource management:

   - Add hotplug reservation only once (not at each level of the
     hierarchy) so bridge windows don't grow more than necessary (Ilpo
     Järvinen)

  Driver binding:

   - Rework device matching so device ID lifetime only needs to cover
     the probe path since dynamic IDs can be removed at any time (Gary
     Guo)

  Error handling:

   - Update mappings of AER errors to agent & layer and log them for
     each individual error when multiple errors detected (Lukas Wunner)

   - Log Error Source only once, not twice in separate messages (Lukas
     Wunner)

   - Emit TLP Log only for unmasked errors (Lukas Wunner)

   - Support Advisory Non-Fatal Errors (Lukas Wunner)

   - Allow DPC on all Downstream Ports, not just Root Ports, when OS
     controls AER (Darshit Shah)

  ASPM:

   - Program the same ASPM Control values for every function of
     multi-function devices, as recommended by the PCIe spec (Krishna
     Chaitanya Chundru)

   - Avoid L0s for Realtek RTS525A, where it causes an AER interrupt
     storm (Max Lee)

   - Avoid ASPM L0s, L1, and L1 PM Substates based on 'aspm-no-l0s',
     'aspm-no-l1' [1], and 'aspm-no-l1ss' DT properties (Krishna
     Chaitanya Chundru)

  Power management:

   - Allow D3 for native hotplug-capable Root Ports on non-x86 platforms
     (we avoid D3 for these ports on x86 because some old platforms
     didn't validate it) (Manivannan Sadhasivam)

   - Allow portdrv to claim Ports even if they don't support services
     (AER, PME, DPC, hotplug, etc) so it can do power management (Brian
     Norris)

  Power control:

   - Add support for PCIe WAKE# interrupt when described via DT (Krishna
     Chaitanya Chundru)

   - For the TC9563 PCIe switch:

       - Take a reference on the I2C adapter to avoid uninterruptible
         hang when unloading an I2C module while in-use (Johan Hovold)

       - Update DT binding and driver to restrict Tx Amplitude, DFE and
         N_FTS to USP, DSP1 and DSP2 (Manivannan Sadhasivam)

       - Power off only external-facing ports (DSP1, DSP2), leaving USP
         and DSP3 (aka VDSP) powered up (Manivannan Sadhasivam)

       - Move integrated MAC Endpoint out of the list of internal ports
         and configure it separately (Manivannan Sadhasivam)

  Virtualization:

   - Add ACS quirk for Pericom PI7C9X2G608 switches (Tim Harvey)

   - Fix a long-standing bug in the Intel PCH Root Port MPC ACS quirk
     that didn't update the intended INTEL_MPC_REG_IRBNCE bit because it
     used a 16-bit config write when a 32-bit write was intended
     (Mohamad Raizudeen)

  Procfs:

   - Avoid spurious runtime PM wakeup on config space accesses that are
     outside config space and fail before reaching PCI (Krzysztof
     Wilczyński)

   - Warn on user-space writes to kernel-exclusive config space regions,
     as we already do for sysfs (Krzysztof Wilczyński)

   - Check credentials of opener, not reader, for config space reads, as
     we already do for sysfs (Krzysztof Wilczyński)

  Sysfs:

   - In pci_write_legacy_io(), avoid out-of-bounds reads from the user
     buffer and fix incorrect ioport write data (1-byte writes on
     little-endian powerpc, 2- and 4-byte writes on big-endian powerpc)
     (Krzysztof Wilczyński)

   - In pci_read_legacy_io(), fix incorrect ioport read data for 2- and
     4-byte reads on big-endian powerpc (Krzysztof Wilczyński)

   - Fix I/O port accessor argument order in Alpha pci_legacy_write()
     (Krzysztof Wilczyński)

   - Avoid spurious runtime PM wakeup on config space accesses that are
     outside config space and fail before reaching PCI (Krzysztof
     Wilczyński)

   - Return -EINVAL, not -ENODEV, for mmap of I/O BAR that fails because
     the arch doesn't support it, as we do for procfs (Krzysztof
     Wilczyński)

   - Check for LOCKDOWN_PCI_ACCESS for legacy_io and legacy_mem, as we
     do for other config space accessors (Krzysztof Wilczyński)

  Peer-to-peer DMA:

   - Add Nvidia Vera Rubin to list of platforms that support P2PDMA
     (Leon Romanovsky)

  Endpoint framework:

   - Check doorbell SUCCESS bit in pci_endpoint_test to avoid treating
     some failures as successes (Niklas Cassel)

   - Fail doorbell test when the trigger IRQ is missed (Niklas Cassel)

  New native PCIe controller drivers:

   - Add DT binding and driver for NVIDIA Tegra264 (Thierry Reding)

  Native PCIe controllers:

   - Use common wait time definitions for PCIe link monitoring instead
     of defining driver-private duplicates (Thierry Reding)

  Generic host bridge driver:

   - Fix NULL pointer dereference that caused enumeration failures on
     32-bit CAM systems (Steffen Persvold)

  Amlogic Meson PCIe controller driver:

   - Correct the PERST# GPIO state so it remains asserted until power
     and REFCLK become stable to fix enumeration failure (Ronald
     Claveau)

  ASPEED PCIe controller driver:

   - Switch to irq_domain_create_linear() so we can obsolete
     irq_domain_add_linear() (Jiri Slaby)

  Cadence PCIe controller driver:

   - Add MODULE_DEVICE_TABLE to generate module aliases for OF-based
     module autoloading (Pengpeng Hou)

   - Add debugfs 'ltssm_status' file for LGA- and HPA-based Cadence
     controllers (Hans Zhang)

   - Support up to x4 (not x2) lanes for J200 (Takuma Fujiwara)

   - Fix host/endpoint dependencies for cadence-plat driver to fix link
     error when cadence-plat is built-in but the host or endpoint driver
     is modular (Aksh Garg)

  Freescale i.MX6 PCIe controller driver:

   - Add imx6 intr/aer/pme interrupt lines for i.MX95 (Richard Zhu)

   - Remove PERST# checking from pci_host_common_parse_port() so callers
     can decide whether to fall back to legacy DT binding with PERST# in
     the host bridge (Sherry Sun)

   - Fix build issues when PCI_PWRCTRL_GENERIC or PCI_HOST_COMMON is a
     module (Arnd Bergmann)

   - Create pwrctrl devices only once by doing it from imx_pcie_probe()
     instead of imx_pcie_host_init(), which is used during both probe
     and resume (Sherry Sun)

   - Use 'dw_pcie_rp->skip_pwrctrl_off' to avoid powering off devices
     during suspend to preserve wakeup capability (Sherry Sun)

   - Add runtime PM support for i.MX95 to allow dynamic power management
     when the link is idle (Richard Zhu)

  Intel VMD host bridge driver:

   - Support device ID 0x28C1 and assume that BIOS has already
     enumerated the hierarchy below VMD and stored bus range info for OS
     to use (Nirmal Patel)

   - Add support for VMCONFIG BUS_RESTRICT_CFG=3, which makes it
     possible to enumerate downstream devices on Intel Arrow Lake-HX
     systems and probably others (Ali Alaei)

   - Pay attention to _OSC negotiation for VMD hierarchy only when
     running on bare metal, not when running in a VM (Nirmal Patel)

   - Add Nova Lake (NVL) and Dunlow (DNL) Device IDs (Szymon Durawa)

  MediaTek PCIe controller driver:

   - Add support for PCIe controller in EcoNet EN7528 and EN751221 SoCs
     (Caleb James DeLisle)

  MediaTek PCIe Gen3 controller driver:

   - Add mediatek-gen3 'memory-region' for restricted DMA buffer
     (Chen-Yu Tsai)

  NVIDIA Tegra264 PCIe controller driver:

   - Distinguish Tegra264 C0 PCIe controller for internal GPU from C1-C5
     controllers so the unit address matches the first 'reg' entry
     (Thierry Reding)

   - Add Tegra264 Root Port stanzas to prepare for generic WAKE#
     handling (Thierry Reding)

  Qualcomm PCIe controller driver:

   - Add IPQ9650 compatible with global interrupt (Kathiravan
     Thirumoorthy)

   - Add IPQ5210 compatible with IPQ9574 fallback (Varadarajan
     Narayanan)

   - Add DT binding and driver support for Hawi SoC (Matthew Leung)

   - Skip PERST# GPIOs provided by downstream PCIe devices, which should
     be handled by drivers of those devices (Manivannan Sadhasivam)

   - Stop advertising Attention Button Present (no Qcom SoCs support
     Attention Buttons) so pciehp can use Presence Detect Changed events
     (Qiang Yu)

  Renesas R-Car PCIe controller driver:

   - Add rcar-gen4-pci-host optional 'msi-parent' for GIT ITS (Marek
     Vasut)

   - When MSI is enabled but iMSI-RX is not used, configure AXIINTC to
     allow GIT ITS to handle MSI (Marek Vasut)

   - Refactor GIC600 implementation to make it easier to add platforms
     that only support 32-bit addressing (Marek Vasut)

   - Add Renesas R-Car Gen4 S4/V4H/V4M to the list of GIC600
     integrations that only support 32-bit addressing (Marek Vasut)

  Renesas RZ/G3S PCIe controller driver:

   - Add DT binding and driver support for RZ/V2H(P) SoC, which contains
     two PCIe controllers, configured either as a single x4 link or two
     independent x2 link controllers (Lad Prabhakar)

  SpacemiT K1 PCIe controller driver:

   - Add missing MODULE_DEVICE_TABLE() to generate module alias info for
     OF-based module autoloading (Pengpeng Hou)

  StarFive PCIe controller driver:

   - Fix resource leaks on error paths in host_init() (Ali Tariq)

   - Fix runtime PM handling and teardown ordering to avoid register
     access while power or clocks are disabled (Ali Tariq)

   - Check for runtime PM resume failure to avoid register access while
     power or clocks are disabled (Ali Tariq)

  Synopsys DesignWare PCIe controller driver:

   - Add LECARC PMU IDs to the DWC RAS/DES VSEC list so it can take
     advantage of the existing debugfs support for silicon debug, error
     injection, and event counters (Brett Zhou)

   - Factor pcie_valid_speed() and pci_bus_speed2lnkctl2() out of bwctrl
     so they can be shared by the DWC core (Hans Zhang)

   - Flush MSI writes from endpoint before unmapping the iATU, as we
     already do for MSI-X writes (Niklas Cassel)

   - Unmap MSI iATU window before mapping MSI-X window, to avoid a
     subsequent MSI write using a disabled aperture and losing the
     interrupt (Niklas Cassel)

   - Change endpoint .pre_init() and .init() callbacks to return errors
     and handle them (Marek Vasut)

  UltraRISC PCIe controller driver:

   - Add 'core', 'dbi', and 'aux' clocks to DT binding and manage them
     in the driver (Jia Wang)

   - Use module_platform_driver() since this may be built as a module,
     though not removable because IRQs can't be safely disposed (Jia
     Wang)

  MicroSemi Switchtec management driver:

   - Add Microchip PCI1008 device ID and include it in NTB DMA alias
     quirk (Logan Gunthorpe)

  Miscellaneous:

   - Document how to write PCI Host Controller drivers (Manivannan
     Sadhasivam)

   - Fix typos in documentation (D'Orus Tsitera)

   - Use %pe format specifier to print error pointers so we get symbolic
     errname when available (Krzysztof Wilczyński)"

* tag 'pci-v7.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: (124 commits)
  PCI: vmd: Add Nova Lake (NVL) and Dunlow (DNL) Device IDs
  PCI: tegra264: Add Tegra264 support
  dt-bindings: PCI: tegra264: Switch to PCIe Root Port bindings
  dt-bindings: PCI: tegra264: Strictly distinguish C0 from C1-C5
  PCI/AER: Support Advisory Non-Fatal Errors
  PCI: Fix 32-bit config write in Intel PCH Root Port MPC ACS quirk
  PCI: dwc: Handle return value from endpoint .pre_init callback
  PCI: dwc: Handle return value from endpoint .init callback
  PCI: dwc: Add PCI ID for LECARC PCIe PMU
  PCI/ASPM: Mask ASPM states based on Devicetree properties
  PCI/ASPM: Disable/restore ASPM on every function for multi-function devices
  Documentation: PCI: Document how to write PCI Host Controller drivers
  PCI/ASPM: Use pcie_capability_clear_and_set_word() for ASPM disable/restore
  PCI: Add support for PCIe WAKE# interrupt
  PCI: Allow D3 for native hotplug-capable Root Ports on non-x86 platforms
  dt-bindings: PCI: Correct white-space style
  PCI/ASPM: Avoid L0s for Realtek RTS525A
  PCI: ultrarisc: Use module_platform_driver()
  PCI: ultrarisc: Get and enable DP1000 PCIe controller clocks
  dt-bindings: PCI: ultrarisc: Add required DP1000 PCIe clocks
  ...
2026-08-23 12:44:10 -07:00
2026-01-26 19:07:09 -08:00
2026-07-15 10:51:29 -06:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer: Getting started with kernel development
* Academic Researcher: Studying kernel internals and architecture
* Security Expert: Hardening and vulnerability analysis
* Backport/Maintenance Engineer: Maintaining stable kernels
* System Administrator: Configuring and troubleshooting
* Maintainer: Leading subsystems and reviewing patches
* Hardware Vendor: Writing drivers for new hardware
* Distribution Maintainer: Packaging kernels for distros
* AI Coding Assistant: LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst
S
Description
No description provided
Readme
5.7 GiB
Languages
C 96.9%
Assembly 0.9%
Rust 0.6%
Shell 0.6%
Python 0.5%
Other 0.3%