Is the List Architecture-Specific or Generic?
============================================

The list provided is **generic** and represents the typical files and directories you would find in ``/sys/bus/pci/devices/0000:00:18.x`` on a **Linux system**. However, there are some nuances to consider.

Generic Nature of the List
-------------------------

- The files and directories listed are common across most Linux systems and architectures (e.g., x86, ARM, PowerPC).
- These files are part of the **Linux kernel's sysfs interface**, which standardizes how device information is exposed to userspace.
- For example, files like ``vendor``, ``device``, ``class``, ``resource``, and ``driver`` are present on almost all systems with PCI devices.

Architecture-Specific or Hardware-Specific Variations
----------------------------------------------------

While the list is generic, some files or directories may **vary depending on**:

- **Architecture**: For example, ARM-based systems might have additional or different files related to platform-specific PCI implementations.
- **Kernel Version**: Newer kernels may expose additional files or directories, while older kernels might lack some of them.
- **Hardware Features**: If the PCI device supports specific features (e.g., SR-IOV, AER, ASPM), the corresponding files (e.g., ``sriov_numvfs``, ``pcie_aer/``) will be present. If the hardware doesn't support these features, the files won't exist.
- **Driver Implementation**: Some files (e.g., ``driver_override``, ``uevent``) depend on how the device driver interacts with the kernel.

Examples of Architecture-Specific or Hardware-Specific Files
-----------------------------------------------------------

Here are some examples of files or directories that might not be present on all systems:

SR-IOV-Related Files
~~~~~~~~~~~~~~~~~~~~

- ``sriov_numvfs``, ``sriov_totalvfs``, ``physfn/``, ``virtfn0/``, etc.
- These only exist if the device supports SR-IOV (Single Root I/O Virtualization).

PCIe-Related Files
~~~~~~~~~~~~~~~~~~

- ``pcie_link_width``, ``pcie_link_speed``, ``pcie_aer/``, ``pcie_aspm/``, etc.
- These are specific to PCI Express (PCIe) devices and won't exist for older PCI devices.

IOMMU-Related Files
~~~~~~~~~~~~~~~~~~~

- ``iommu_group/``, ``iommu/``
- These depend on whether the system has an IOMMU (Input-Output Memory Management Unit) and whether it's enabled.

NUMA-Related Files
~~~~~~~~~~~~~~~~~~

- ``numa_node``
- This file is only relevant on systems with NUMA (Non-Uniform Memory Access) architecture.

How to Check for Specific Files
-------------------------------

If you're unsure whether a file or directory exists on your system, you can use the following command to list the contents of the directory for a specific device:

.. code-block:: bash

   ls /sys/bus/pci/devices/0000:00:18.0

Replace ``0000:00:18.0`` with the actual device address you're investigating.

Summary
-------

- The list is **generic** and applies to most Linux systems with PCI devices.
- Some files or directories may **not exist** depending on the architecture, kernel version, hardware features, or driver implementation.
- If you're working on a specific architecture or hardware platform, you may encounter additional files or directories not included in the generic list.

If you're working on a specific architecture or hardware platform and notice differences, feel free to share the details, and I can help you interpret or adapt the list accordingly!