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Date:   Thu, 17 Feb 2022 13:12:57 +0300
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Subject: Re: [PATCH v6 00/21] Introduce power-off+restart call chain API
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To:     Helge Deller <deller@gmx.de>,
        "Rafael J. Wysocki" <rafael@kernel.org>
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References: <20220130233718.21544-1-digetx@gmail.com>
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 <de2cbd2a-8d0d-8678-e514-b153d04546cc@gmx.de>
From:   Dmitry Osipenko <digetx@gmail.com>
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16.02.2022 23:30, Helge Deller пишет:
> On 2/16/22 13:25, Rafael J. Wysocki wrote:
>> On Tue, Feb 15, 2022 at 11:00 PM Dmitry Osipenko <digetx@gmail.com> wrote:
>>>
>>> 31.01.2022 02:36, Dmitry Osipenko пишет:
>>>> Problem
>>>> -------
>>>>
>>>> SoC devices require power-off call chaining functionality from kernel.
>>>> We have a widely used restart chaining provided by restart notifier API,
>>>> but nothing for power-off.
>>>>
>>>> Solution
>>>> --------
>>>>
>>>> Introduce new API that provides both restart and power-off call chains.
>>>>
>>>> Why combine restart with power-off? Because drivers often do both.
>>>> More practical to have API that provides both under the same roof.
>>>>
>>>> The new API is designed with simplicity and extensibility in mind.
>>>> It's built upon the existing restart and reboot APIs. The simplicity
>>>> is in new helper functions that are convenient for drivers. The
>>>> extensibility is in the design that doesn't hardcode callback
>>>> arguments, making easy to add new parameters and remove old.
>>>>
>>>> This is a third attempt to introduce the new API. First was made by
>>>> Guenter Roeck back in 2014, second was made by Thierry Reding in 2017.
>>>> In fact the work didn't stop and recently arm_pm_restart() was removed
>>>> from v5.14 kernel, which was a part of preparatory work started by
>>>> Guenter Roeck. I took into account experience and ideas from the
>>>> previous attempts, extended and polished them.
>>>
>>>
>>> Rafael and all, do you see anything critical that needs to be improved
>>> in this v6?
>>>
>>> Will be great if you could take this patchset via the power tree if it
>>> looks okay, or give an ack.
>>
>> I need some more time for this, sorry.

No worries, we're not in a rush.

>> I'm a bit concerned about seeing no response to this set from anyone.
>>
>> It looks like multiple platforms may be affected by it in principle,
>> so doesn't anyone care?

The platforms that didn't provide ack so far are: SH, x86, IA64, MIPS
and NDS32. At least x86 and MIPS are alive, not sure why maintainers
didn't bother to answer yet.

> I did looked into the whole patch set after applying it locally.
> 
> While I agree a new combined API is good, and the beginning looked promising,
> after some time I started to ask myself if the whole infrastructure might
> be a little overdesigned.
> 
> Anyway, I tested it and it works for me on parisc.
> And it's probably better than what we have today.

Thank you!