[Intel-xe] [PATCH v2 0/6] Add HWMON support for DGFX

[Guenter Roeck]

On 7/14/23 13:21, Rodrigo Vivi wrote:
[ ... ]

> Hi Guenter,
> 
> First of all sorry for jumping late here. I'm totally with you here and we should
> definitely only use the new API. For standard entries that will definitely
> reduce the code size.
> 
> So, since we are talking about reducing code here, and looking to other DRM
> drivers, and thinking about the needs on this new Xe driver, I'm wondering
> if you would consider accepting 'frequency' as a standard hwmon attribute.
> 
> We would need it to be RW so we could use to put freq requests as well,
> and possibly different types/domains and even throttle reasons on top.
> 
> So we could then try to unify all the drm drivers in a common drm-hwmon
> layer putting an end in all abuses and deprecated users.
> 
> But before moving fwd with any proposal I'd like to hear your thoughts on
> this 'frequency' block as standard attribute.
> 

I really don't see how this would fit under "hardware monitoring".
Making it writable would be even worse - this is most definitely not a limit but
an actual value. The notion of limit actually shows that it is not a good fit as
a monitoring attribute: I can not conceive the notion of a "maximum" or "minimum"
frequency limit, or an "under" or "over" frequency.

If this is about thermal control/management, you might want to consider registering
with devfreq and the thermal subsystem (see devfreq_cooling_register() and
friends for reference).

Thanks,
Guenter