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Date:   Sun, 27 Feb 2022 17:56:31 +0000
From:   Paul Cercueil <paul@crapouillou.net>
Subject: Re: [PATCH -next] misc: rtsx: fix build for CONFIG_PM not set
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Randy Dunlap <rdunlap@infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Wei WANG <wei_wang@realsil.com.cn>,
        Kai-Heng Feng <kai.heng.feng@canonical.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>
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Le dim., f?vr. 27 2022 at 18:51:38 +0100, Arnd Bergmann 
<arnd@arndb.de> a ?crit :
> On Sun, Feb 27, 2022 at 6:46 PM Paul Cercueil <paul@crapouillou.net> 
> wrote:
>>  Le dim., f?vr. 27 2022 at 18:30:16 +0100, Arnd Bergmann
>> 
>>  There could be a DEFINE_DEV_PM_OPS(), but I don't think that's 
>> really
>>  needed - you can very well declare your struct dev_pm_ops without 
>> using
>>  one of these macros. Just make sure to use the SYSTEM_SLEEP_PM_OPS /
>>  RUNTIME_PM_OPS macros for the callbacks and pm_ptr() for the 
>> device.pm
>>  pointer.
> 
> Ah, of course, so it comes down to
> s/SET_SYSTEM_SLEEP_PM_OPS/SYSTEM_SLEEP_PM_OPS/ while
> removing all the #ifdef an __maybe_unused annotations. The pm_ptr()
> in driver.pm makes this slightly more optimized AFAICT, but has no
> effect on behavior, right?

The use of SYSTEM_SLEEP_PM_OPS makes sure that the callbacks are 
dropped if the dev_pm_ops is dead code, and the pm_ptr() must be used 
for the compiler to know that the dev_pm_ops is dead code.

-Paul