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

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Message-ID: <25015664-22a7-2d4b-7ba7-ef9611fb3045@quicinc.com>
Date: Mon, 7 Oct 2024 12:38:49 +0530
From: Sibi Sankar <quic_sibis@...cinc.com>
To: Sudeep Holla <sudeep.holla@....com>, Ulf Hansson <ulf.hansson@...aro.org>
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



On 8/15/24 19:16, Sudeep Holla wrote:
> On Thu, Aug 15, 2024 at 12:46:15PM +0200, Ulf Hansson wrote:
>> On Wed, 14 Aug 2024 at 15:31, Sudeep Holla <sudeep.holla@....com> wrote:
>>>
>>> On Wed, Aug 14, 2024 at 02:38:24PM +0200, Ulf Hansson wrote:
>>>>
>>>> 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.
>>>>
>>>
>>> Yes, I did come to the conclusion that this is inevitable but hadn't
>>> thought much on the exact solution. This email and you merging the original
>>> patch made me think a bit quickly now 😉
>>
>> Alright, great!
>>
>>>
>>>> I have therefore decided to queue up $subject patch for fixes. Please
>>>> let me know if you have any other proposals/objections moving forward.
>>>
>>> The original patch may not work well with the use case Peng presented.
>>> As the name and id may also match in their case, I was wondering if we
>>> need to add some prefix like perf- or something to avoid the potential
>>> clash across power and perf genpds ? I may be missing something still as
>>> it is hard to visualise all possible case that can happen with variety
>>> of platform and their firmware.
>>>
>>> In short, happy to have some fix for the issue in some form whichever
>>> works for wider set of platforms.
>>
>> Okay, so I have dropped the $subject patch from my fixes branch for
>> now, to allow us and Sibi to come up with an improved approach.
>>
>> That said, it looks to me that the proper fix needs to involve
>> pm_genpd_init() in some way, as this problem with unique device naming
>> isn't really limited to SCMI. Normally we use an "ida" to get a unique
>> index that we tag on to the device's name, but maybe there is a better
>> strategy here!?
> 
> Yes using "ida" for unique index might work here as well AFAIU. It can be
> one of the possible solution for sure.

Just re-spun it with ida, I've also shared how the output looks
with those additional device ids added to the device name. Have
a look at it when you get time.

-Sibi

>