Hi,

On 5/21/19 5:18 PM, Michael Ellerman wrote:

Anju T Sudhakar [off-list ref] writes:

quoted

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