VIO bus not initialized

[Michael Ellerman]

Paul Menzel <pmenzel at molgen.mpg.de> writes:
> Am 15.03.21 um 08:53 schrieb Michael Ellerman:
>> Paul Menzel writes:
>
>>> On the POWER8 system IBM S822LC, Linux 5.12-rc2+ logs the errors below.
>> 
>> That's a bare metal system, you can see that from the line "Using
>> PowerNV machine description" in the boot log.
>> 
>>>       $ dmesg --level=err
>>>       [    1.555668] Driver 'hvc_console' was unable to register with bus_type 'vio' because the bus was not initialized.
>>>       [    1.558434] Driver 'tpm_ibmvtpm' was unable to register with bus_type 'vio' because the bus was not initialized.
>>>       $ grep VIO /boot/config-5.12.0-rc2+
>>>       CONFIG_IBMVIO=y
>> 
>> The "vio" bus is not a real bus, it's a fake bus we use for hypervisor
>> provided devices in LPARs (guests).
>> 
>> So on bare metal machines there is no vio bus, the devices that would
>> appear on the vio bus are found via other mechanisms.
>
> Thank you for the explanation. Two questions:
>
> 1.  Could a bare metal system be detected, and the VIO “be skipped”?

Yeah, in fact we are already skipping the registration of the bus,
that's why we're seeing these messages. We need to also skip the
registration of the drivers to avoid those warnings.

See the patch I just sent.

cheers