Message-ID: <4f0d1b50-9f55-dd81-f0c7-f5e0dfd75c2a@gmail.com>
Date:   Thu, 17 Feb 2022 13:12:57 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Helge Deller <deller@....de>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-csky@...r.kernel.org, linux-ia64@...r.kernel.org,
        linux-m68k@...ts.linux-m68k.org,
        "open list:BROADCOM NVRAM DRIVER" <linux-mips@...r.kernel.org>,
        linux-parisc@...r.kernel.org, linux-riscv@...ts.infradead.org,
        Linux-sh list <linux-sh@...r.kernel.org>,
        xen-devel@...ts.xenproject.org,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        linux-tegra <linux-tegra@...r.kernel.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Guo Ren <guoren@...nel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Greg Ungerer <gerg@...ux-m68k.org>,
        Joshua Thompson <funaho@...ai.org>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Sebastian Reichel <sre@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Greentime Hu <green.hu@...il.com>,
        Vincent Chen <deanbo422@...il.com>,
        "James E.J. Bottomley" <James.Bottomley@...senpartnership.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        the arch/x86 maintainers <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Len Brown <lenb@...nel.org>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, Pavel Machek <pavel@....cz>,
        Lee Jones <lee.jones@...aro.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Ulf Hansson <ulf.hansson@...aro.org>, alankao@...estech.com,
        "K . C . Kuen-Chern Lin" <kclin@...estech.com>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>
Subject: Re: [PATCH v6 00/21] Introduce power-off+restart call chain API

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@...il.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!

Powered by blists - more mailing lists