Hi,

Anju T Sudhakar <anju@linux.vnet.ibm.com> writes:

Currently init_imc_pmu() can be failed either because
an IMC unit with invalid domain(i.e an IMC node not
supported by the kernel) is attempted a pmu-registration
or something went wrong while registering a valid IMC unit.
In both the cases kernel provides a 'Registration failed'
error message.

Example:
Log message, when trace-imc node is not supported by the kernel, and the
skiboot supports trace-imc node.

So for kernel, trace-imc node is now an unknown domain.

[    1.731870] nest_phb5_imc performance monitor hardware support registered
[    1.731944] nest_powerbus0_imc performance monitor hardware support registered
[    1.734458] thread_imc performance monitor hardware support registered
[    1.734460] IMC Unknown Device type
[    1.734462] IMC PMU (null) Register failed
[    1.734558] nest_xlink0_imc performance monitor hardware support registered
[    1.734614] nest_xlink1_imc performance monitor hardware support registered
[    1.734670] nest_xlink2_imc performance monitor hardware support registered
[    1.747043] Initialise system trusted keyrings
[    1.747054] Key type blacklist registered


To avoid ambiguity on the error message, return for invalid domain
before attempting a pmu registration. 

What do we print once the patch is applied?

Once the patch is applied, we return for invalid domains. so we will only have

`IMC Unknown Device type` message printed for unknown domains.

And `IMC PMU (null) Register failed` message will appear only if the

registration fails for a known domain.

Thanks,

Anju