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

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Message-ID: <CAPDyKFrESupeNS4BO8TPHPGpXFLsNqLPrUEw3xzr8oh8FsLHeA@mail.gmail.com>
Date: Wed, 14 Aug 2024 14:38:24 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Sudeep Holla <sudeep.holla@....com>, Sibi Sankar <quic_sibis@...cinc.com>
Cc: cristian.marussi@....com, linux-kernel@...r.kernel.org, 
	arm-scmi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org, 
	quic_rgottimu@...cinc.com, quic_kshivnan@...cinc.com, johan@...nel.org, 
	Peng Fan <peng.fan@....com>
Subject: Re: [PATCH] pmdomain: arm: Fix debugfs node creation failure

+ Peng

On Fri, 5 Jul 2024 at 15:04, Sudeep Holla <sudeep.holla@....com> 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.

Sudeep, while I understand your point and I agree with it, it's really
a simple fix that $subject patch is proposing. As the unique name
isn't mandated by the SCMI spec, it looks to me that we should make a
fix for it on the Linux side.

I have therefore decided to queue up $subject patch for fixes. Please
let me know if you have any other proposals/objections moving forward.

Kind regards
Uffe