Re: [PATCH 3/4] drm/drm_ras: Add DRM RAS netlink error event notification

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

On 3/25/2026 7:01 PM, Raag Jadav wrote:
> On Wed, Mar 11, 2026 at 03:59:17PM +0530, Riana Tauro wrote:
>> Add support for asynchronous error notifications in drm_ras.
> It's either drm_ras or DRM RAS, make it consistent in all patches
> (both commit message and subject).
Sure.
>
>> Define a new `error-event` netlink event and a new multicast
>> group `error-notify` in drm_ras spec. Each event contains
>> a node-id and error-id to identify the type and source
>> of error.
>>
>> Add drm_ras_error_notify() to trigger this event from drivers.
>> Userspace can receive this event by subscribing to the
>> multicast group error-notify.
>>
>> Example: Using ynl tool
> Ditto. Either Usage or Example, make it consistent in all patches.
>
> Also, please utilize the full 75 character space where possible.

Will fix.

>
>> $ sudo ynl --family drm_ras --subscribe error-notify
>>
>> Cc: Jakub Kicinski <kuba@kernel.org>
>> Cc: Zack McKevitt <zachary.mckevitt@oss.qualcomm.com>
>> Cc: Lijo Lazar <lijo.lazar@amd.com>
>> Cc: Hawking Zhang <Hawking.Zhang@amd.com>
>> Cc: David S. Miller <davem@davemloft.net>
>> Cc: Paolo Abeni <pabeni@redhat.com>
>> Cc: Eric Dumazet <edumazet@google.com>
>> Signed-off-by: Riana Tauro <riana.tauro@intel.com>
>> ---
>>   Documentation/gpu/drm-ras.rst            |  9 +++++
>>   Documentation/netlink/specs/drm_ras.yaml | 14 +++++++
>>   drivers/gpu/drm/drm_ras.c                | 48 ++++++++++++++++++++++++
>>   drivers/gpu/drm/drm_ras_nl.c             |  6 +++
>>   drivers/gpu/drm/drm_ras_nl.h             |  4 ++
>>   include/drm/drm_ras.h                    |  2 +
>>   include/uapi/drm/drm_ras.h               |  3 ++
>>   7 files changed, 86 insertions(+)
>>
>> diff --git a/Documentation/gpu/drm-ras.rst b/Documentation/gpu/drm-ras.rst
>> index 4636e68f5678..09b2918f67bd 100644
>> --- a/Documentation/gpu/drm-ras.rst
>> +++ b/Documentation/gpu/drm-ras.rst
>> @@ -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.
>> +* Listen to ``error-event`` notifications for error events by subscribing to the
>> +  ``error-notify`` multicast group.
>>   
>>   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: Listen to error events
>> +
>> +.. code-block:: bash
>> +
>> +    sudo ynl --family drm_ras --subscribe error-notify
>> +    {'msg': {'error-id': 1, 'node-id': 1}, 'name': 'error-event'}
> Can we also have error-name and node-name? I'd be pulling my hair off
> if I need to remember all the ids.

Yeah makes sense. We can add the node_name, error_name.
Adding device_name would also be more useful in the event.

@Rodrigo/@aravind thoughts?

>
> On that note, I think it'll be good to have them as part of request
> attributes as an alternative to ids (also for existing commands) but
> that can done as a follow up.
>
We cannot use names as alternative because it won't work for multiple cards.
example in xe: Suppose there are 2 cards and each has 2 nodes. We cannot 
query using node_name+error_name.
Also most of the netlink implementations use id's as unique identifiers.

$ sudo ./cli.py --family drm_ras  --dump list-nodes
[{'device-name': 'bdf_1', 'node-id': 0, 'node-name': 
'correctable-errors', 'node-type': 'error-counter'},
  {'device-name': 'bdf_1, 'node-id': 1, 'node-name': 
'uncorrectable-errors', 'node-type': 'error-counter'},
  {'device-name': 'bdf_2', 'node-id': 2, 'node-name': 
'correctable-errors', 'node-type': 'error-counter'},
  {'device-name': 'bdf_2', 'node-id': 3, 'node-name': 
'uncorrectable-errors', 'node-type': 'error-counter'}]

>
> Also, what if I have multiple devices with multiple nodes. Do they need
> separate subscription?
>
No, we subscribe only to the group not the nodes. In this case the group 
is 'error-notify'

$ sudo ./cli.py --family drm_ras --subscribe error-notify
{'msg': {'error-id': 1, 'node-id': 1}, 'name': 'error-event'}
{'msg': {'error-id': 1, 'node-id': 3}, 'name': 'error-event'}


Thanks
Riana
>
> Raag