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SubjectRe: [PATCH V1 RESEND 1/3] perf/imx_ddr: Add system PMU identifier for userspace
>>>> I also really dislike this. What's the preferred way to identify the
>>>> SoC
>>>> from userspace?
>>> /proc/cpuinfo? ;)
>> The *SoC*!
>>> For an non-firmware specific case, I'd say soc_device should be. I'd
>>> guess ACPI systems don't use it and for them it's dmidecode typically.
>>> The other problem I have with soc_device is it is optional.
> Hi Will,
>> John -- what do you think about using soc_device to expose this
>> information,
>> with ACPI systems using DMI data instead?
> Generally I don't think that DMI is reliable, and I saw this as the
> least preferred choice. I'm looking at the sysfs DMI info for my dev
> board, and I don't even see anything like a SoC identifier.
> As for the event_source device sysfs identifier file, it would not
> always contain effectively the same as the SoC ID.
> Certain PMUs which I'm interested in plan to have probe-able
> identification info available in future.

BTW, Shaokun now tells me that the HiSi uncore PMU HW have such
registers to identify the implementation. I didn't know.

So we could add that identifier file for those PMUs as proof-of-concept,
exposing that register.

As for other PMUs which I'm interested in, again, future versions should
have such registers to self-identify.

So using something derived from the DT compat string would hopefully be
the uncommon case.


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