From e24328974a88aa8541e94e8bb8dfa2ade1b3c45d Mon Sep 17 00:00:00 2001 From: Donggeun Yoo Date: Wed, 2 Sep 2026 00:21:26 +0900 Subject: iio: proximity: vl53l0x-i2c: claim direct mode for raw reads vl53l0x_read_raw() starts a single-shot ranging measurement and reads back the result. Once the triggered buffer is enabled the sensor runs in continuous mode and its data-ready interrupt is routed to the trigger, so a concurrent in_distance_raw read disturbs the streaming setup and never gets its completion, returning -ETIMEDOUT. The original submission claimed direct mode here, but it was dropped during review because the driver had no buffer support at the time [1]. Continuous (buffered) mode was later added without restoring the claim [2], reintroducing the conflict. Reject direct reads while buffered capture is active by claiming direct mode around the measurement, as the vl53l1x sibling already does. Fixes: 762186c6e7b1 ("iio: proximity: vl53l0x-i2c: Added continuous mode support") Link: https://lore.kernel.org/linux-iio/20180911160300.GA9212@himanshu-Vostro-3559/ [1] Link: https://lore.kernel.org/linux-iio/20240909101508.263085-3-abhashkumarjha123@gmail.com/ [2] Signed-off-by: Donggeun Yoo Cc: stable@vger.kernel.org Signed-off-by: Jonathan Cameron --- Documentation/gpu/drm-ras.rst | 113 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 113 insertions(+) create mode 100644 Documentation/gpu/drm-ras.rst (limited to 'Documentation/gpu/drm-ras.rst') diff --git a/Documentation/gpu/drm-ras.rst b/Documentation/gpu/drm-ras.rst new file mode 100644 index 000000000..83c21853b --- /dev/null +++ b/Documentation/gpu/drm-ras.rst @@ -0,0 +1,113 @@ +.. 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. + +.. contents:: + +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. +* Clear specific error counters with the ``clear-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} + +Example: Clear an error counter for a given node + +.. code-block:: bash + + sudo ynl --family drm_ras --do clear-error-counter --json '{"node-id":0, "error-id":1}' + None -- cgit v1.3.1