lkml.org 
[lkml]   [2020]   [May]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH V1 RESEND 1/3] perf/imx_ddr: Add system PMU identifier for userspace
Date
>>>>
>>>> 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.

Cheers,
John

\
 
 \ /
  Last update: 2020-05-27 16:36    [W:0.054 / U:6.828 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site