Re: [External] Re: [PATCH] [RFC] Documentation: Add documentation for new platform_profile sysfs attribute

[Mark Pearson]

Thanks Hans

On 26/10/2020 14:33, Hans de Goede wrote:
> Hi Mark,
>
> Thank you for this new version.
>
> On 10/26/20 6:44 PM, Mark Pearson wrote:
> > From: Hans de Goede <hdegoede@xxxxxxxxxx>
<snip>

> > +
> > +If for some reason there is no good match when mapping then a new profile-name
> > +may be added. Drivers which wish to introduce new profile-names must:
> > +1. Have very good reasons to do so.
> > +2. Add the new profile-name to this document, so that future drivers which also
> > +   have a similar problem can use the same new.
>
> s/same new/same name/
I've read this document so many times...I'm not sure how I missed that 
one. Thanks.
> > + Usually new profile-names will
> > +   be added to the "extra profile-names" section of this document. But in some
> > +   cases the set of standard profile-names may be extended.
>
> With the change from a more generic API to this new one more targeted towards DPTF
> I would drop this part.
OK - I have some questions then related to this change, below
> > +
> > +What:		/sys/firmware/acpi/platform_profile_choices
> > +Date:		October 2020
> > +Contact:	Hans de Goede <hdegoede@xxxxxxxxxx>
> > +Description:
> > +		Reading this file gives a space separated list of profiles
> > +		supported for this device.
> > +
> > +		Drivers must use the following standard profile-names whenever
> > +		possible:
> > +
> > +		low-power:		Emphasises low power consumption
> > +		quiet:			Offers quieter operation (lower fan
> > +					speed but with higher performance and
> > +					temperatures then seen in low-power
>
> I think the description here is a bit too specific, this may cause userspace
> to have expectations which are not necessary true. I would describe this as
> just:
>
> 		quiet:			Emphasises quieter operation
Agreed. I'll update

> > +		balanced:		Balance between low power consumption
> > +					and performance
> > +		performance:		Emphasises performance (and may lead to
> > +					higher temperatures and fan speeds)
> > +
> > +		Userspace may expect drivers to offer at least several of these
> > +		standard profile-names! If none of the above are a good match
> > +		for some of the drivers profiles, then drivers may use one of
> > +		these extra profile-names:
> > +		<reserved for future use>
> > +
If we remove the extra profile-names section above then I think it 
should be removed here too. If someone wants to add a new 'mode' then it 
would be added to the list of 'standard names', and becomes a new 
option. Wanted to check I'm not missing something important.

> > +What:		/sys/firmware/acpi/platform_profile
> > +Date:		October 2020
> > +Contact:	Hans de Goede <hdegoede@xxxxxxxxxx>
> > +Description:
> > +		Reading this file gives the current selected profile for this
> > +		device. Writing this file with one of the strings from
> > +		available_profiles changes the profile to the new value.
>
> The part about custom profiles below may be dropped. That was intended for use
> with e.g. GPUs but since this now strictly is a system-level profile API, the
> part below can be dropped now.
Agreed
> > +
> > +		Reading this file may also return "custom". This is intended for
> > +		drivers which have and export multiple knobs. Such drivers may
> > +		very well still want to offer a set of profiles for easy of use
> > +		and to be able to offer a consistent standard API (this API) to
> > +		userspace for configuring their performance. The "custom" value
> > +		is intended for when ai user has directly configured the knobs
> > +		(through e.g. some advanced control-panel for a GPU) and the
> > +		knob values do not match any of the presets represented by the
> > +		platform-profiles. In this case writing this file will
> > +		override the modifications and restore the selected presets.
> > +
>
> Regards,
>
> Hans
Thanks!
mark