Re: [PATCH v1 02/11] drm/ras: Introduce get-error-threshold

["Tauro, Riana" <riana.tauro@intel.com>]

On 4/18/2026 2:46 AM, Raag Jadav wrote:
> Add get-error-threshold command support which allows querying threshold
> value of the error. 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.
>
> Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> ---
>   Documentation/gpu/drm-ras.rst            |   8 ++
>   Documentation/netlink/specs/drm_ras.yaml |  37 ++++++++
>   drivers/gpu/drm/drm_ras.c                | 103 +++++++++++++++++++++++
>   drivers/gpu/drm/drm_ras_nl.c             |  13 +++
>   drivers/gpu/drm/drm_ras_nl.h             |   2 +
>   include/drm/drm_ras.h                    |  14 +++
>   include/uapi/drm/drm_ras.h               |  11 +++
>   7 files changed, 188 insertions(+)
>
> diff --git a/Documentation/gpu/drm-ras.rst b/Documentation/gpu/drm-ras.rst
> index 70b246a78fc8..6443dfd1677f 100644
> --- a/Documentation/gpu/drm-ras.rst
> +++ b/Documentation/gpu/drm-ras.rst
> @@ -52,6 +52,8 @@ User space tools can:
>     as a parameter.
>   * Query specific error counter values with the ``get-error-counter`` command, using both
>     ``node-id`` and ``error-id`` as parameters.
> +* Query specific error threshold value with the ``get-error-threshold`` command, using both
> +  ``node-id`` and ``error-id`` as parameters.
Also define what is a thresold. How can it be used?
>   
>   YAML-based Interface
>   --------------------
> @@ -101,3 +103,9 @@ Example: Query an error counter for a given node
>       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: Query threshold value of a given error
> +
> +.. 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': 0}
> diff --git a/Documentation/netlink/specs/drm_ras.yaml b/Documentation/netlink/specs/drm_ras.yaml
> index 79af25dac3c5..95a939fb987d 100644
> --- a/Documentation/netlink/specs/drm_ras.yaml
> +++ b/Documentation/netlink/specs/drm_ras.yaml
> @@ -69,6 +69,25 @@ attribute-sets:
>           name: error-value
>           type: u32
>           doc: Current value of the requested error counter.
> +  -
> +    name: error-threshold-attrs
> +    attributes:
> +      -
> +        name: node-id
> +        type: u32
> +        doc: Node ID targeted by this operation.
> +      -
> +        name: error-id
> +        type: u32
> +        doc: Unique identifier for a specific error within the node.
> +      -
> +        name: error-name
> +        type: string
> +        doc: Name of the error.
> +      -
> +        name: error-threshold
> +        type: u32
> +        doc: Threshold value of the error.
>   
>   operations:
>     list:
> @@ -113,3 +132,21 @@ operations:
>               - node-id
>           reply:
>             attributes: *errorinfo
> +    -
> +      name: get-error-threshold
> +      doc: >-
> +           Retrieve threshold value of the error.
> +           The response includes the id, the name, and current threshold
> +           value of the error.
> +      attribute-set: error-threshold-attrs
> +      flags: [admin-perm]
> +      do:
> +        request:
> +          attributes:
> +            - node-id
> +            - error-id
> +        reply:
> +          attributes:
> +            - error-id
> +            - error-name
> +            - error-threshold
> diff --git a/drivers/gpu/drm/drm_ras.c b/drivers/gpu/drm/drm_ras.c
> index 1f7435d60f11..d2d853d5d69c 100644
> --- a/drivers/gpu/drm/drm_ras.c
> +++ b/drivers/gpu/drm/drm_ras.c
> @@ -37,6 +37,10 @@
>    *    Returns all counters of a node if only Node ID is provided or specific
>    *    error counters.
>    *
> + * 3. GET_ERROR_THRESHOLD: Query threshold value of the error.
> + *    Userspace must provide Node ID and Error ID.
> + *    Returns the threshold value of a specific error.
> + *
>    * Node registration:
>    *
>    * - drm_ras_node_register(): Registers a new node and assigns
> @@ -66,6 +70,8 @@
>    *   operation, fetching all counters from a specific node.
>    * - drm_ras_nl_get_error_counter_doit(): Implements the GET_ERROR_COUNTER doit
>    *   operation, fetching a counter value from a specific node.
> + * - drm_ras_nl_get_error_threshold_doit(): Implements the GET_ERROR_THRESHOLD doit
> + *   operation, fetching the threshold value of a specific error.
>    */
>   
>   static DEFINE_XARRAY_ALLOC(drm_ras_xa);
> @@ -162,6 +168,22 @@ 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 *value)
> +{
> +	struct drm_ras_node *node;
> +
> +	node = xa_load(&drm_ras_xa, node_id);
> +	if (!node || !node->query_error_threshold)
> +		return -ENOENT;

For the absence of the function, 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, value);
> +}
> +
>   static int msg_reply_counter_value(struct sk_buff *msg, u32 error_id,
>   				   const char *error_name, u32 value)
>   {
> @@ -180,6 +202,24 @@ static int msg_reply_counter_value(struct sk_buff *msg, u32 error_id,
>   			   value);
>   }
>   
> +static int msg_reply_threshold_value(struct sk_buff *msg, u32 error_id,
> +				     const char *error_name, u32 value)
> +{
> +	int ret;
> +
> +	ret = nla_put_u32(msg, DRM_RAS_A_ERROR_THRESHOLD_ATTRS_ERROR_ID, error_id);
> +	if (ret)
> +		return ret;
> +
> +	ret = nla_put_string(msg, DRM_RAS_A_ERROR_THRESHOLD_ATTRS_ERROR_NAME,
> +			     error_name);
> +	if (ret)
> +		return ret;
> +
> +	return nla_put_u32(msg, DRM_RAS_A_ERROR_THRESHOLD_ATTRS_ERROR_THRESHOLD,
> +			   value);
> +}
> +
>   static int doit_reply_counter_value(struct genl_info *info, u32 node_id,
>   				    u32 error_id)
>   {
> @@ -216,6 +256,42 @@ static int doit_reply_counter_value(struct genl_info *info, u32 node_id,
>   	return genlmsg_reply(msg, info);
>   }
>   
> +static int doit_reply_threshold_value(struct genl_info *info, u32 node_id,
> +				      u32 error_id)
> +{
> +	struct sk_buff *msg;
> +	struct nlattr *hdr;
> +	const char *error_name;
> +	u32 value;
> +	int ret;
> +
> +	msg = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
> +	if (!msg)
> +		return -ENOMEM;
> +
> +	hdr = genlmsg_iput(msg, info);
> +	if (!hdr) {
> +		nlmsg_free(msg);
> +		return -EMSGSIZE;
> +	}
> +
> +	ret = get_node_error_threshold(node_id, error_id,
> +				       &error_name, &value);
> +	if (ret)
> +		return ret;

You have to cancel and free genlmsg here.
Looks like the counter patch also has the same issue. Will send out a fix.

> +
> +	ret = msg_reply_threshold_value(msg, error_id, error_name, value);
> +	if (ret) {
> +		genlmsg_cancel(msg, hdr);
> +		nlmsg_free(msg);
> +		return ret;
> +	}
> +
> +	genlmsg_end(msg, hdr);
> +
> +	return genlmsg_reply(msg, info);
> +}
> +
>   /**
>    * drm_ras_nl_get_error_counter_dumpit() - Dump all Error Counters
>    * @skb: Netlink message buffer
> @@ -314,6 +390,33 @@ int drm_ras_nl_get_error_counter_doit(struct sk_buff *skb,
>   	return doit_reply_counter_value(info, node_id, error_id);
>   }
>   
> +/**
> + * drm_ras_nl_get_error_threshold_doit() - Query threshold value of the error
Nit: an

Thanks
Riana
> + * @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 current threshold of the corresponding error. 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_THRESHOLD_ATTRS_NODE_ID) ||
> +	    GENL_REQ_ATTR_CHECK(info, DRM_RAS_A_ERROR_THRESHOLD_ATTRS_ERROR_ID))
> +		return -EINVAL;
> +
> +	node_id = nla_get_u32(info->attrs[DRM_RAS_A_ERROR_THRESHOLD_ATTRS_NODE_ID]);
> +	error_id = nla_get_u32(info->attrs[DRM_RAS_A_ERROR_THRESHOLD_ATTRS_ERROR_ID]);
> +
> +	return doit_reply_threshold_value(info, node_id, error_id);
> +}
> +
>   /**
>    * 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 16803d0c4a44..48e231734f4d 100644
> --- a/drivers/gpu/drm/drm_ras_nl.c
> +++ b/drivers/gpu/drm/drm_ras_nl.c
> @@ -22,6 +22,12 @@ static const struct nla_policy drm_ras_get_error_counter_dump_nl_policy[DRM_RAS_
>   	[DRM_RAS_A_ERROR_COUNTER_ATTRS_NODE_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_THRESHOLD_ATTRS_ERROR_ID + 1] = {
> +	[DRM_RAS_A_ERROR_THRESHOLD_ATTRS_NODE_ID] = { .type = NLA_U32, },
> +	[DRM_RAS_A_ERROR_THRESHOLD_ATTRS_ERROR_ID] = { .type = NLA_U32, },
> +};
> +
>   /* Ops table for drm_ras */
>   static const struct genl_split_ops drm_ras_nl_ops[] = {
>   	{
> @@ -43,6 +49,13 @@ static const struct genl_split_ops drm_ras_nl_ops[] = {
>   		.maxattr	= DRM_RAS_A_ERROR_COUNTER_ATTRS_NODE_ID,
>   		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DUMP,
>   	},
> +	{
> +		.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_THRESHOLD_ATTRS_ERROR_ID,
> +		.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 06ccd9342773..540fe22e2312 100644
> --- a/drivers/gpu/drm/drm_ras_nl.h
> +++ b/drivers/gpu/drm/drm_ras_nl.h
> @@ -18,6 +18,8 @@ int drm_ras_nl_get_error_counter_doit(struct sk_buff *skb,
>   				      struct genl_info *info);
>   int drm_ras_nl_get_error_counter_dumpit(struct sk_buff *skb,
>   					struct netlink_callback *cb);
> +int drm_ras_nl_get_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 5d50209e51db..50cee70bd065 100644
> --- a/include/drm/drm_ras.h
> +++ b/include/drm/drm_ras.h
> @@ -57,6 +57,20 @@ struct drm_ras_node {
>   	 */
>   	int (*query_error_counter)(struct drm_ras_node *node, u32 error_id,
>   				   const char **name, u32 *val);
> +	/**
> +	 * @query_error_threshold:
> +	 *
> +	 * This callback is used by drm-ras to query threshold value of a
> +	 * specific error.
> +	 *
> +	 * 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 *val);
>   
>   	/** @priv: Driver private data */
>   	void *priv;
> diff --git a/include/uapi/drm/drm_ras.h b/include/uapi/drm/drm_ras.h
> index 5f40fa5b869d..49c5ca497d73 100644
> --- a/include/uapi/drm/drm_ras.h
> +++ b/include/uapi/drm/drm_ras.h
> @@ -38,9 +38,20 @@ enum {
>   	DRM_RAS_A_ERROR_COUNTER_ATTRS_MAX = (__DRM_RAS_A_ERROR_COUNTER_ATTRS_MAX - 1)
>   };
>   
> +enum {
> +	DRM_RAS_A_ERROR_THRESHOLD_ATTRS_NODE_ID = 1,
> +	DRM_RAS_A_ERROR_THRESHOLD_ATTRS_ERROR_ID,
> +	DRM_RAS_A_ERROR_THRESHOLD_ATTRS_ERROR_NAME,
> +	DRM_RAS_A_ERROR_THRESHOLD_ATTRS_ERROR_THRESHOLD,
> +
> +	__DRM_RAS_A_ERROR_THRESHOLD_ATTRS_MAX,
> +	DRM_RAS_A_ERROR_THRESHOLD_ATTRS_MAX = (__DRM_RAS_A_ERROR_THRESHOLD_ATTRS_MAX - 1)
> +};
> +
>   enum {
>   	DRM_RAS_CMD_LIST_NODES = 1,
>   	DRM_RAS_CMD_GET_ERROR_COUNTER,
> +	DRM_RAS_CMD_GET_ERROR_THRESHOLD,
>   
>   	__DRM_RAS_CMD_MAX,
>   	DRM_RAS_CMD_MAX = (__DRM_RAS_CMD_MAX - 1)