Re: [PATCH] pmdomain: arm: Fix debugfs node creation failure

[Sibi Sankar]

On 7/5/24 18:34, Sudeep Holla wrote:
> On Fri, Jul 05, 2024 at 09:16:29AM +0530, Sibi Sankar wrote:
> > On 7/4/24 16:02, Sudeep Holla wrote:
> > > If there are 2 perf domains for a device or group of devices, there must
> > > be something unique about each of these domains. Why can't the firmware
> > > specify the uniqueness or the difference via the name?
> > >
> > > The example above seems firmware is being just lazy to update it. Also
> > > for the user/developer/debugger, the unique name might be more useful
> > > than just this number.
> > >
> > > So please use the name(we must now have extended name if 16bytes are less)
> > > to provide unique names. Please stop working around such silly firmware
> > > bugs like this, it just makes using debugfs for anything useful harder.
> >
> > This is just meant to address firmware that are already out in the wild.
> > That being said I don't necessarily agree with the patch either since
> > it's penalizing firmware that actually uses a proper name by appending
> > something inherently less useful to it. Since, the using of an unique
> > domain name isn't required by the spec, the need for it goes under the radar
> > for vendors. Mandating it might be the right thing to do since
> > the kernel seems inherently expect that.
>
> Well I would love if spec authors can agree and mandate this. But this is
> one of those things I can't argue as I don't necessarily agree with the
> argument. There are 2 distinct/unique domains but firmware authors ran out
> of unique names for them or just can't be bothered to care about it.
>
> They can't run out of characters as well in above examples, firmware can
> add some useless domain ID in the name if they can't be bothered or creative.
>
> So I must admit I can't be bothered as well with that honestly.

Okay, I guess the conclusion is that if the firmware vendors
don't care enough to provide unique names, they get to live
without those debugfs nodes.

Do we really want to register/expose scmi perf power-domains used by
the CPU nodes? Given that scmi-cpufreq doesn't consume these power
domains and can be voted upon by another consumer, wouldn't this cause
a disconnect?

-Sibi

> --
> Regards,
> Sudeep