Re: [PATCH v4 2/5] drm/ras: Introduce error threshold

[Raag Jadav <raag.jadav@intel.com>]

Hi Jakub,

On Tue, Jun 23, 2026 at 03:39:56PM +0530, Raag Jadav wrote:
> Add get-error-threshold and set-error-threshold command support which
> allows querying/setting error threshold of the counter. Threshold in RAS
> context means the number of errors the hardware is expected to accumulate
> before it raises them to software. This is to have a fine grained control
> over error notifications that are raised by the hardware.

Anything I can do to move this forward?

> Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> ---
> v2: Document threshold definition (Riana)
>     Return -EOPNOTSUPP on threshold callbacks absence (Riana)
>     Cancel and free genlmsg on failure (Riana)
>     Document threshold bounds checking responsibility (Riana)
> v3: Move documentation from yaml to rst file (Riana)
>     s/value/threshold (Riana)
>     Use goto for error handling (Riana)
> v4: Clarify 0 threshold expectations (Riana)
>     Drop redundant wrapping (Riana)
> ---
>  Documentation/gpu/drm-ras.rst            |  18 +++
>  Documentation/netlink/specs/drm_ras.yaml |  32 +++++
>  drivers/gpu/drm/drm_ras.c                | 161 +++++++++++++++++++++++
>  drivers/gpu/drm/drm_ras_nl.c             |  27 ++++
>  drivers/gpu/drm/drm_ras_nl.h             |   4 +
>  include/drm/drm_ras.h                    |  28 ++++
>  include/uapi/drm/drm_ras.h               |   3 +
>  7 files changed, 273 insertions(+)
> 
> diff --git a/Documentation/gpu/drm-ras.rst b/Documentation/gpu/drm-ras.rst
> index 83c21853b74b..2718f8aee09d 100644
> --- a/Documentation/gpu/drm-ras.rst
> +++ b/Documentation/gpu/drm-ras.rst
> @@ -56,6 +56,10 @@ User space tools can:
>    ``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.
> +* Query specific error counter threshold with the ``get-error-threshold`` command, using both
> +  ``node-id`` and ``error-id`` as parameters.
> +* Set specific error counter threshold with the ``set-error-threshold`` command, using
> +  ``node-id``, ``error-id`` and ``error-threshold`` as parameters.
>  
>  YAML-based Interface
>  --------------------
> @@ -111,3 +115,17 @@ Example: Clear an error counter for a given node
>  
>      sudo ynl --family drm_ras --do clear-error-counter --json '{"node-id":0, "error-id":1}'
>      None
> +
> +Example: Query error threshold of a given counter
> +
> +.. code-block:: bash
> +
> +    sudo ynl --family drm_ras --do get-error-threshold --json '{"node-id":0, "error-id":1}'
> +    {'error-id': 1, 'error-name': 'error_name1', 'error-threshold': 16}
> +
> +Example: Set error threshold of a given counter
> +
> +.. code-block:: bash
> +
> +    sudo ynl --family drm_ras --do set-error-threshold --json '{"node-id":0, "error-id":1, "error-threshold":8}'
> +    None
> diff --git a/Documentation/netlink/specs/drm_ras.yaml b/Documentation/netlink/specs/drm_ras.yaml
> index e113056f8c01..9cf7f9cde242 100644
> --- a/Documentation/netlink/specs/drm_ras.yaml
> +++ b/Documentation/netlink/specs/drm_ras.yaml
> @@ -69,6 +69,10 @@ attribute-sets:
>          name: error-value
>          type: u32
>          doc: Current value of the requested error counter.
> +      -
> +        name: error-threshold
> +        type: u32
> +        doc: Error threshold of the counter.
>  
>  operations:
>    list:
> @@ -124,3 +128,31 @@ operations:
>        do:
>          request:
>            attributes: *id-attrs
> +    -
> +      name: get-error-threshold
> +      doc: >-
> +           Retrieve error threshold of a given counter.
> +           The response includes the id, the name, and current threshold
> +           of the counter.
> +      attribute-set: error-counter-attrs
> +      flags: [admin-perm]
> +      do:
> +        request:
> +          attributes: *id-attrs
> +        reply:
> +          attributes:
> +            - error-id
> +            - error-name
> +            - error-threshold
> +    -
> +      name: set-error-threshold
> +      doc: >-
> +           Set error threshold of a given counter.
> +      attribute-set: error-counter-attrs
> +      flags: [admin-perm]
> +      do:
> +        request:
> +          attributes:
> +            - node-id
> +            - error-id
> +            - error-threshold
> diff --git a/drivers/gpu/drm/drm_ras.c b/drivers/gpu/drm/drm_ras.c
> index 467a169026fc..d60c40ac5427 100644
> --- a/drivers/gpu/drm/drm_ras.c
> +++ b/drivers/gpu/drm/drm_ras.c
> @@ -41,6 +41,13 @@
>   *    Userspace must provide Node ID, Error ID.
>   *    Clears specific error counter of a node if supported.
>   *
> + * 4. GET_ERROR_THRESHOLD: Query error threshold of a given counter.
> + *    Userspace must provide Node ID and Error ID.
> + *    Returns the error threshold of a specific counter.
> + *
> + * 5. SET_ERROR_THRESHOLD: Set error threshold of a given counter.
> + *    Userspace must provide Node ID, Error ID and threshold to be set.
> + *
>   * Node registration:
>   *
>   * - drm_ras_node_register(): Registers a new node and assigns
> @@ -61,6 +68,16 @@
>   *     + The error counters in the driver doesn't need to be contiguous, but the
>   *       driver must return -ENOENT to the query_error_counter as an indication
>   *       that the ID should be skipped and not listed in the netlink API.
> + *     + The driver can optionally implement query_error_threshold() and
> + *       set_error_threshold() callbacks to facilitate getting/setting error
> + *       threshold of the counter. Threshold in RAS context means the number of
> + *       errors the hardware is expected to accumulate before it raises them to
> + *       software. This is to have a fine grained control over error notifications
> + *       that are raised by the hardware.
> + *     + The driver is responsible for error threshold bounds checking.
> + *     + Threshold of 0 can mean invalid threshold or act as a disable notifications
> + *       toggle for that counter depending on usecase and the driver is responsible
> + *       for handling it as needed.
>   *
>   * Netlink handlers:
>   *
> @@ -72,6 +89,10 @@
>   *   operation, fetching a counter value from a specific node.
>   * - drm_ras_nl_clear_error_counter_doit(): Implements the CLEAR_ERROR_COUNTER doit
>   *   operation, clearing a counter value from a specific node.
> + * - drm_ras_nl_get_error_threshold_doit(): Implements the GET_ERROR_THRESHOLD doit
> + *   operation, fetching the error threshold of a specific counter.
> + * - drm_ras_nl_set_error_threshold_doit(): Implements the SET_ERROR_THRESHOLD doit
> + *   operation, setting the error threshold of a specific counter.
>   */
>  
>  static DEFINE_XARRAY_ALLOC(drm_ras_xa);
> @@ -168,6 +189,40 @@ static int get_node_error_counter(u32 node_id, u32 error_id,
>  	return node->query_error_counter(node, error_id, name, value);
>  }
>  
> +static int get_node_error_threshold(u32 node_id, u32 error_id, const char **name, u32 *threshold)
> +{
> +	struct drm_ras_node *node;
> +
> +	node = xa_load(&drm_ras_xa, node_id);
> +	if (!node)
> +		return -ENOENT;
> +
> +	if (!node->query_error_threshold)
> +		return -EOPNOTSUPP;
> +
> +	if (error_id < node->error_counter_range.first || error_id > node->error_counter_range.last)
> +		return -EINVAL;
> +
> +	return node->query_error_threshold(node, error_id, name, threshold);
> +}
> +
> +static int set_node_error_threshold(u32 node_id, u32 error_id, u32 threshold)
> +{
> +	struct drm_ras_node *node;
> +
> +	node = xa_load(&drm_ras_xa, node_id);
> +	if (!node)
> +		return -ENOENT;
> +
> +	if (!node->set_error_threshold)
> +		return -EOPNOTSUPP;
> +
> +	if (error_id < node->error_counter_range.first || error_id > node->error_counter_range.last)
> +		return -EINVAL;
> +
> +	return node->set_error_threshold(node, error_id, threshold);
> +}
> +
>  static int msg_reply_value(struct sk_buff *msg, u32 error_id,
>  			   const char *error_name, u32 value)
>  {
> @@ -186,6 +241,22 @@ static int msg_reply_value(struct sk_buff *msg, u32 error_id,
>  			   value);
>  }
>  
> +static int msg_reply_threshold(struct sk_buff *msg, u32 error_id, const char *error_name,
> +			       u32 threshold)
> +{
> +	int ret;
> +
> +	ret = nla_put_u32(msg, DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID, error_id);
> +	if (ret)
> +		return ret;
> +
> +	ret = nla_put_string(msg, DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_NAME, error_name);
> +	if (ret)
> +		return ret;
> +
> +	return nla_put_u32(msg, DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_THRESHOLD, threshold);
> +}
> +
>  static int doit_reply_value(struct genl_info *info, u32 node_id,
>  			    u32 error_id)
>  {
> @@ -225,6 +296,43 @@ static int doit_reply_value(struct genl_info *info, u32 node_id,
>  	return ret;
>  }
>  
> +static int doit_reply_threshold(struct genl_info *info, u32 node_id, u32 error_id)
> +{
> +	const char *error_name;
> +	struct sk_buff *msg;
> +	struct nlattr *hdr;
> +	u32 threshold;
> +	int ret;
> +
> +	msg = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
> +	if (!msg)
> +		return -ENOMEM;
> +
> +	hdr = genlmsg_iput(msg, info);
> +	if (!hdr) {
> +		ret = -EMSGSIZE;
> +		goto free_msg;
> +	}
> +
> +	ret = get_node_error_threshold(node_id, error_id, &error_name, &threshold);
> +	if (ret)
> +		goto cancel_msg;
> +
> +	ret = msg_reply_threshold(msg, error_id, error_name, threshold);
> +	if (ret)
> +		goto cancel_msg;
> +
> +	genlmsg_end(msg, hdr);
> +
> +	return genlmsg_reply(msg, info);
> +
> +cancel_msg:
> +	genlmsg_cancel(msg, hdr);
> +free_msg:
> +	nlmsg_free(msg);
> +	return ret;
> +}
> +
>  /**
>   * drm_ras_nl_get_error_counter_dumpit() - Dump all Error Counters
>   * @skb: Netlink message buffer
> @@ -358,6 +466,59 @@ int drm_ras_nl_clear_error_counter_doit(struct sk_buff *skb,
>  	return node->clear_error_counter(node, error_id);
>  }
>  
> +/**
> + * drm_ras_nl_get_error_threshold_doit() - Query error threshold of a counter
> + * @skb: Netlink message buffer
> + * @info: Generic Netlink info containing attributes of the request
> + *
> + * Extracts the Node ID and Error ID from the netlink attributes and retrieves
> + * the error threshold of the corresponding counter. Sends the result back to
> + * the requesting user via the standard Genl reply.
> + *
> + * Return: 0 on success, or negative errno on failure.
> + */
> +int drm_ras_nl_get_error_threshold_doit(struct sk_buff *skb, struct genl_info *info)
> +{
> +	u32 node_id, error_id;
> +
> +	if (!info->attrs ||
> +	    GENL_REQ_ATTR_CHECK(info, DRM_RAS_A_ERROR_COUNTER_ATTRS_NODE_ID) ||
> +	    GENL_REQ_ATTR_CHECK(info, DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID))
> +		return -EINVAL;
> +
> +	node_id = nla_get_u32(info->attrs[DRM_RAS_A_ERROR_COUNTER_ATTRS_NODE_ID]);
> +	error_id = nla_get_u32(info->attrs[DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID]);
> +
> +	return doit_reply_threshold(info, node_id, error_id);
> +}
> +
> +/**
> + * drm_ras_nl_set_error_threshold_doit() - Set error threshold of a counter
> + * @skb: Netlink message buffer
> + * @info: Generic Netlink info containing attributes of the request
> + *
> + * Extracts the Node ID, Error ID and threshold from the netlink attributes and
> + * sets the error threshold of the corresponding counter.
> + *
> + * Return: 0 on success, or negative errno on failure.
> + */
> +int drm_ras_nl_set_error_threshold_doit(struct sk_buff *skb, struct genl_info *info)
> +{
> +	u32 node_id, error_id, threshold;
> +
> +	if (!info->attrs ||
> +	    GENL_REQ_ATTR_CHECK(info, DRM_RAS_A_ERROR_COUNTER_ATTRS_NODE_ID) ||
> +	    GENL_REQ_ATTR_CHECK(info, DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID) ||
> +	    GENL_REQ_ATTR_CHECK(info, DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_THRESHOLD))
> +		return -EINVAL;
> +
> +	node_id = nla_get_u32(info->attrs[DRM_RAS_A_ERROR_COUNTER_ATTRS_NODE_ID]);
> +	error_id = nla_get_u32(info->attrs[DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID]);
> +	threshold = nla_get_u32(info->attrs[DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_THRESHOLD]);
> +
> +	return set_node_error_threshold(node_id, error_id, threshold);
> +}
> +
>  /**
>   * drm_ras_node_register() - Register a new RAS node
>   * @node: Node structure to register
> diff --git a/drivers/gpu/drm/drm_ras_nl.c b/drivers/gpu/drm/drm_ras_nl.c
> index dea1c1b2494e..02e8e5054d05 100644
> --- a/drivers/gpu/drm/drm_ras_nl.c
> +++ b/drivers/gpu/drm/drm_ras_nl.c
> @@ -28,6 +28,19 @@ static const struct nla_policy drm_ras_clear_error_counter_nl_policy[DRM_RAS_A_E
>  	[DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID] = { .type = NLA_U32, },
>  };
>  
> +/* DRM_RAS_CMD_GET_ERROR_THRESHOLD - do */
> +static const struct nla_policy drm_ras_get_error_threshold_nl_policy[DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID + 1] = {
> +	[DRM_RAS_A_ERROR_COUNTER_ATTRS_NODE_ID] = { .type = NLA_U32, },
> +	[DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID] = { .type = NLA_U32, },
> +};
> +
> +/* DRM_RAS_CMD_SET_ERROR_THRESHOLD - do */
> +static const struct nla_policy drm_ras_set_error_threshold_nl_policy[DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_THRESHOLD + 1] = {
> +	[DRM_RAS_A_ERROR_COUNTER_ATTRS_NODE_ID] = { .type = NLA_U32, },
> +	[DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID] = { .type = NLA_U32, },
> +	[DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_THRESHOLD] = { .type = NLA_U32, },
> +};
> +
>  /* Ops table for drm_ras */
>  static const struct genl_split_ops drm_ras_nl_ops[] = {
>  	{
> @@ -56,6 +69,20 @@ static const struct genl_split_ops drm_ras_nl_ops[] = {
>  		.maxattr	= DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID,
>  		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
>  	},
> +	{
> +		.cmd		= DRM_RAS_CMD_GET_ERROR_THRESHOLD,
> +		.doit		= drm_ras_nl_get_error_threshold_doit,
> +		.policy		= drm_ras_get_error_threshold_nl_policy,
> +		.maxattr	= DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID,
> +		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
> +	},
> +	{
> +		.cmd		= DRM_RAS_CMD_SET_ERROR_THRESHOLD,
> +		.doit		= drm_ras_nl_set_error_threshold_doit,
> +		.policy		= drm_ras_set_error_threshold_nl_policy,
> +		.maxattr	= DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_THRESHOLD,
> +		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
> +	},
>  };
>  
>  struct genl_family drm_ras_nl_family __ro_after_init = {
> diff --git a/drivers/gpu/drm/drm_ras_nl.h b/drivers/gpu/drm/drm_ras_nl.h
> index a398643572a5..57b1e647d833 100644
> --- a/drivers/gpu/drm/drm_ras_nl.h
> +++ b/drivers/gpu/drm/drm_ras_nl.h
> @@ -20,6 +20,10 @@ int drm_ras_nl_get_error_counter_dumpit(struct sk_buff *skb,
>  					struct netlink_callback *cb);
>  int drm_ras_nl_clear_error_counter_doit(struct sk_buff *skb,
>  					struct genl_info *info);
> +int drm_ras_nl_get_error_threshold_doit(struct sk_buff *skb,
> +					struct genl_info *info);
> +int drm_ras_nl_set_error_threshold_doit(struct sk_buff *skb,
> +					struct genl_info *info);
>  
>  extern struct genl_family drm_ras_nl_family;
>  
> diff --git a/include/drm/drm_ras.h b/include/drm/drm_ras.h
> index f2a787bc4f64..683a3844f84f 100644
> --- a/include/drm/drm_ras.h
> +++ b/include/drm/drm_ras.h
> @@ -69,6 +69,34 @@ struct drm_ras_node {
>  	 */
>  	int (*clear_error_counter)(struct drm_ras_node *node, u32 error_id);
>  
> +	/**
> +	 * @query_error_threshold:
> +	 *
> +	 * This callback is used by drm-ras to query error threshold of a
> +	 * specific counter.
> +	 *
> +	 * Driver should expect query_error_threshold() to be called with
> +	 * error_id from `error_counter_range.first` to
> +	 * `error_counter_range.last`.
> +	 *
> +	 * Returns: 0 on success, negative error code on failure.
> +	 */
> +	int (*query_error_threshold)(struct drm_ras_node *node, u32 error_id, const char **name,
> +				     u32 *threshold);
> +	/**
> +	 * @set_error_threshold:
> +	 *
> +	 * This callback is used by drm-ras to set error threshold of a specific
> +	 * counter.
> +	 *
> +	 * Driver should expect set_error_threshold() to be called with error_id
> +	 * from `error_counter_range.first` to `error_counter_range.last`.
> +	 * Driver is responsible for error threshold bounds checking.
> +	 *
> +	 * Returns: 0 on success, negative error code on failure.
> +	 */
> +	int (*set_error_threshold)(struct drm_ras_node *node, u32 error_id, u32 threshold);
> +
>  	/** @priv: Driver private data */
>  	void *priv;
>  };
> diff --git a/include/uapi/drm/drm_ras.h b/include/uapi/drm/drm_ras.h
> index 218a3ee86805..27c68956495f 100644
> --- a/include/uapi/drm/drm_ras.h
> +++ b/include/uapi/drm/drm_ras.h
> @@ -33,6 +33,7 @@ enum {
>  	DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_ID,
>  	DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_NAME,
>  	DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_VALUE,
> +	DRM_RAS_A_ERROR_COUNTER_ATTRS_ERROR_THRESHOLD,
>  
>  	__DRM_RAS_A_ERROR_COUNTER_ATTRS_MAX,
>  	DRM_RAS_A_ERROR_COUNTER_ATTRS_MAX = (__DRM_RAS_A_ERROR_COUNTER_ATTRS_MAX - 1)
> @@ -42,6 +43,8 @@ enum {
>  	DRM_RAS_CMD_LIST_NODES = 1,
>  	DRM_RAS_CMD_GET_ERROR_COUNTER,
>  	DRM_RAS_CMD_CLEAR_ERROR_COUNTER,
> +	DRM_RAS_CMD_GET_ERROR_THRESHOLD,
> +	DRM_RAS_CMD_SET_ERROR_THRESHOLD,
>  
>  	__DRM_RAS_CMD_MAX,
>  	DRM_RAS_CMD_MAX = (__DRM_RAS_CMD_MAX - 1)
> -- 
> 2.43.0
>