.. SPDX-License-Identifier: GPL-2.0+

============================ DRM RAS over Generic Netlink

The DRM RAS (Reliability, Availability, Serviceability) interface provides a standardized way for GPU/accelerator drivers to expose error counters and other reliability nodes to user space via Generic Netlink. This allows diagnostic tools, monitoring daemons, or test infrastructure to query hardware health in a uniform way across different DRM drivers.

Key Goals:

• Provide a standardized RAS solution for GPU and accelerator drivers, enabling data center monitoring and reliability operations.
• Implement a single drm-ras Generic Netlink family to meet modern Netlink YAML specifications and centralize all RAS-related communication in one namespace.
• Support a basic error counter interface, addressing the immediate, essential monitoring needs.
• Offer a flexible, future-proof interface that can be extended to support additional types of RAS data in the future.
• Allow multiple nodes per driver, enabling drivers to register separate nodes for different IP blocks, sub-blocks, or other logical subdivisions as applicable.

Nodes

Nodes are logical abstractions representing an error type or error source within the device. Currently, only error counter nodes is supported.

Drivers are responsible for registering and unregistering nodes via the drm_ras_node_register() and drm_ras_node_unregister() APIs.

Node Management

.. kernel-doc:: drivers/gpu/drm/drm_ras.c :doc: DRM RAS Node Management .. kernel-doc:: drivers/gpu/drm/drm_ras.c :internal:

Generic Netlink Usage

The interface is implemented as a Generic Netlink family named drm-ras. User space tools can:

• List registered nodes with the list-nodes command.
• List all error counters in an node with the get-error-counter command with node-id as a parameter.
• Query specific error counter values with the get-error-counter command, using both node-id and error-id as parameters.

YAML-based Interface

The interface is described in a YAML specification Documentation/netlink/specs/drm_ras.yaml

This YAML is used to auto-generate user space bindings via tools/net/ynl/pyynl/ynl_gen_c.py, and drives the structure of netlink attributes and operations.

Usage Notes

• User space must first enumerate nodes to obtain their IDs.
• Node IDs or Node names can be used for all further queries, such as error counters.
• Error counters can be queried by either the Error ID or Error name.
• Query Parameters should be defined as part of the uAPI to ensure user interface stability.
• The interface supports future extension by adding new node types and additional attributes.

Example: List nodes using ynl

.. code-block:: bash

sudo ynl --family drm_ras --dump list-nodes
[{'device-name': '0000:03:00.0',
'node-id': 0,
'node-name': 'correctable-errors',
'node-type': 'error-counter'},
{'device-name': '0000:03:00.0',
 'node-id': 1,
 'node-name': 'uncorrectable-errors',
 'node-type': 'error-counter'}]

Example: List all error counters using ynl

.. code-block:: bash

sudo ynl --family drm_ras --dump get-error-counter --json '{"node-id":0}'
[{'error-id': 1, 'error-name': 'error_name1', 'error-value': 0},
{'error-id': 2, 'error-name': 'error_name2', 'error-value': 0}]

Example: Query an error counter for a given node

.. code-block:: bash

sudo ynl --family drm_ras --do get-error-counter --json '{"node-id":0, "error-id":1}'
{'error-id': 1, 'error-name': 'error_name1', 'error-value': 0}