[PATCH 2/3] cxl: Introduce module parameter 'enable_psltrace'

[Vaibhav Jain]

Thanks for reviewing the patch Christophe,

christophe lombard <clombard at linux.vnet.ibm.com> writes:
>> +bool cxl_enable_psltrace = true;
>> +module_param_named(enable_psltrace, cxl_enable_psltrace, bool, 0600);
>> +MODULE_PARM_DESC(enable_psltrace, "Set PSL traces on probe. default: on");
>> +
> I am not too agree to add a new parameter. This can cause doubts.
> PSL team has confirmed that enabling traces has no impact.
> Do you see any reason to disable the traces ?

Traces on PSL follow a 'set and fetch' model. So once the trace buffer for
a specific array is full it will stop and switch to 'FIN' state and at
that point we need to fetch the trace-data and reinit the array to
re-arm it.

There might be some circumstances where this model may lead to confusion
specifically when AFU developers assume that the trace arrays are
already armed and dont re-arm it causing miss of trace data.

So this module param is a compromise to keep the old behaviour of traces
array intact where in the arming/disarming of the trace arrays is
controlled completely by userspace tooling and not by cxl.

-- 
Vaibhav Jain <vaibhav at linux.vnet.ibm.com>
Linux Technology Center, IBM India Pvt. Ltd.