Re: [PATCH v2 2/9] drm/ras: Introduce get-error-threshold

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

On 5/13/2026 12:46 AM, Raag Jadav wrote:
> Add get-error-threshold command support which allows querying threshold
> value of an 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>
> ---
> v2: Document threshold definition (Riana)
>      Return -EOPNOTSUPP on threshold callbacks absence (Riana)
>      Cancel and free genlmsg on failure (Riana)
> ---
>   Documentation/gpu/drm-ras.rst            |   9 ++
>   Documentation/netlink/specs/drm_ras.yaml |  28 +++++-
>   drivers/gpu/drm/drm_ras.c                | 109 +++++++++++++++++++++++
>   drivers/gpu/drm/drm_ras_nl.c             |  13 +++
>   drivers/gpu/drm/drm_ras_nl.h             |   2 +
>   include/drm/drm_ras.h                    |  15 ++++
>   include/uapi/drm/drm_ras.h               |   2 +
>   7 files changed, 176 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/gpu/drm-ras.rst b/Documentation/gpu/drm-ras.rst
> index 4636e68f5678..dfa72e8becda 100644
> --- a/Documentation/gpu/drm-ras.rst
> +++ b/Documentation/gpu/drm-ras.rst

Can you add the threshold definition in this document. This will be 
published.

> @@ -54,6 +54,8 @@ 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 threshold value with the ``get-error-threshold`` command, using both
> +  ``node-id`` and ``error-id`` as parameters.
>   
>   YAML-based Interface
>   --------------------
> @@ -109,3 +111,10 @@ 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 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': 16}
> diff --git a/Documentation/netlink/specs/drm_ras.yaml b/Documentation/netlink/specs/drm_ras.yaml
> index e113056f8c01..016d713069bb 100644
> --- a/Documentation/netlink/specs/drm_ras.yaml
> +++ b/Documentation/netlink/specs/drm_ras.yaml
> @@ -8,8 +8,10 @@ doc: >-
>     DRM RAS (Reliability, Availability, Serviceability) over Generic Netlink.
>     Provides a standardized mechanism for DRM drivers to register "nodes"
>     representing hardware/software components capable of reporting error counters.
> -  Userspace tools can query the list of nodes or individual error counters
> -  via the Generic Netlink interface.
> +  Userspace tools can query the list of nodes or individual error counters or
> +  their thresholds via the Generic Netlink interface. Threshold in RAS context
> +  means the number of errors the hardware is expected to accumulate before it
> +  raises them to software.
>   
>   definitions:
>     -
> @@ -69,6 +71,10 @@ attribute-sets:
>           name: error-value
>           type: u32
>           doc: Current value of the requested error counter.
> +      -
> +        name: error-threshold
> +        type: u32
> +        doc: Threshold value of the error counter.
>   
>   operations:
>     list:
> @@ -124,3 +130,21 @@ operations:
>         do:
>           request:
>             attributes: *id-attrs
> +    -
> +      name: get-error-threshold
> +      doc: >-
> +           Retrieve threshold value of an error.
> +           The response includes the id, the name, and current threshold
> +           value of the error.
> +      attribute-set: error-counter-attrs
> +      flags: [admin-perm]
> +      do:
> +        request:
> +          attributes:
> +            - node-id
> +            - error-id
use *id-attrs
> +        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 03db53d03329..87e57bd1e8ad 100644
> --- a/drivers/gpu/drm/drm_ras.c
> +++ b/drivers/gpu/drm/drm_ras.c
> @@ -41,6 +41,10 @@
>    *    Userspace must provide Node ID, Error ID.
>    *    Clears specific error counter of a node if supported.
>    *
> + * 4. GET_ERROR_THRESHOLD: Query threshold value of an 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
> @@ -72,6 +76,8 @@
>    *   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 threshold value of a specific error.
>    */
>   
>   static DEFINE_XARRAY_ALLOC(drm_ras_xa);
> @@ -168,6 +174,25 @@ 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)
> +		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, value);
> +}
> +
>   static int msg_reply_counter_value(struct sk_buff *msg, u32 error_id,
>   				   const char *error_name, u32 value)
>   {
> @@ -186,6 +211,24 @@ 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)
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,
> +			   value);
> +}
> +
>   static int doit_reply_counter_value(struct genl_info *info, u32 node_id,
>   				    u32 error_id)
>   {
> @@ -222,6 +265,45 @@ 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;
Threshold?
> +	int ret;
Nit: follow inverted xmas tree
> +
> +	msg = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
> +	if (!msg)
> +		return -ENOMEM;
> +
> +	hdr = genlmsg_iput(msg, info);
> +	if (!hdr) {
> +		nlmsg_free(msg);
use goto

Thanks
Riana

> +		return -EMSGSIZE;
> +	}
> +
> +	ret = get_node_error_threshold(node_id, error_id,
> +				       &error_name, &value);
> +	if (ret) {
> +		genlmsg_cancel(msg, hdr);
> +		nlmsg_free(msg);
> +		return ret;
> +	}
> +
> +	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
> @@ -355,6 +437,33 @@ 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 threshold value of an error
> + * @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 threshold value 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_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_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 dea1c1b2494e..ecec2041c758 100644
> --- a/drivers/gpu/drm/drm_ras_nl.c
> +++ b/drivers/gpu/drm/drm_ras_nl.c
> @@ -28,6 +28,12 @@ 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, },
> +};
> +
>   /* Ops table for drm_ras */
>   static const struct genl_split_ops drm_ras_nl_ops[] = {
>   	{
> @@ -56,6 +62,13 @@ 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,
> +	},
>   };
>   
>   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..399280c2c6e1 100644
> --- a/drivers/gpu/drm/drm_ras_nl.h
> +++ b/drivers/gpu/drm/drm_ras_nl.h
> @@ -20,6 +20,8 @@ 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);
>   
>   extern struct genl_family drm_ras_nl_family;
>   
> diff --git a/include/drm/drm_ras.h b/include/drm/drm_ras.h
> index f2a787bc4f64..7bb429d85f57 100644
> --- a/include/drm/drm_ras.h
> +++ b/include/drm/drm_ras.h
> @@ -69,6 +69,21 @@ 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 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 218a3ee86805..59530f987ba2 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 +43,7 @@ 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_MAX,
>   	DRM_RAS_CMD_MAX = (__DRM_RAS_CMD_MAX - 1)