Re: [PATCH v2 1/6] PM: core: Remove DEFINE_UNIVERSAL_DEV_PM_OPS() macro

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Le ven., janv. 7 2022 at 17:40:57 +0100, Ulf Hansson <ulf.hansson@xxxxxxxxxx> a écrit :
On Fri, 7 Jan 2022 at 17:37, Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote:

 Hi Ulf,

 Le ven., janv. 7 2022 at 17:26:07 +0100, Ulf Hansson
 <ulf.hansson@xxxxxxxxxx> a écrit :
 > On Wed, 5 Jan 2022 at 19:29, Paul Cercueil <paul@xxxxxxxxxxxxxxx>
 > wrote:
 >>
 >>  The deprecated UNIVERSAL_DEV_PM_OPS() macro uses the provided
 >> callbacks
>> for both runtime PM and system sleep, which is very likely to be a >> mistake, as a system sleep can be triggered while a given device is >> already PM-suspended, which would cause the suspend callback to be
 >>  called twice.
 >>
 >>  The amount of users of UNIVERSAL_DEV_PM_OPS() is also tiny (16
 >>  occurences) compared to the number of places where
>> SET_SYSTEM_SLEEP_PM_OPS() is used with pm_runtime_force_suspend()
 >> and
>> pm_runtime_force_resume(), which makes me think that none of these
 >> cases
 >>  are actually valid.
 >>
>> As this macro is currently unused, remove it before someone starts
 >> to
 >>  use it in yet another invalid case.
 >
 > I assume you refer to DEFINE_UNIVERSAL_DEV_PM_OPS here. Can you
 > perhaps make that more clear?

 I can.

 >>
 >>  Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
 >>  Acked-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
 >>  ---
 >>
 >>  Notes:
 >>      v2: No change
 >>
 >>   include/linux/pm.h | 19 ++++++-------------
 >>   1 file changed, 6 insertions(+), 13 deletions(-)
 >>
 >>  diff --git a/include/linux/pm.h b/include/linux/pm.h
 >>  index e1e9402180b9..31bbaafb06d2 100644
 >>  --- a/include/linux/pm.h
 >>  +++ b/include/linux/pm.h
 >>  @@ -366,6 +366,12 @@ static const struct dev_pm_ops name = { \
 >>          SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
 >>   }
 >>
 >>  +/* Deprecated. Use DEFINE_SIMPLE_DEV_PM_OPS() instead. */
 >>  +#define SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \
 >>  +const struct dev_pm_ops __maybe_unused name = { \
 >>  +       SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
 >>  +}
 >>  +
 >>   /*
>> * Use this for defining a set of PM operations to be used in all
 >> situations
 >>    * (system suspend, hibernation or runtime PM).
 >>  @@ -379,19 +385,6 @@ static const struct dev_pm_ops name = { \
>> * .resume_early(), to the same routines as .runtime_suspend() and
 >>    * .runtime_resume(), respectively (and analogously for
 >> hibernation).
 >>    */
>> -#define DEFINE_UNIVERSAL_DEV_PM_OPS(name, suspend_fn, resume_fn,
 >> idle_fn) \
 >>  -static const struct dev_pm_ops name = { \
 >>  -       SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
 >>  -       RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn) \
 >>  -}
 >>  -
 >>  -/* Deprecated. Use DEFINE_SIMPLE_DEV_PM_OPS() instead. */
 >>  -#define SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \
 >>  -const struct dev_pm_ops __maybe_unused name = { \
 >>  -       SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
 >>  -}
 >>  -
 >>  -/* Deprecated. Use DEFINE_UNIVERSAL_DEV_PM_OPS() instead. */
 >
 > Shouldn't this macro be deprecated any more?

 I can only deprecate it if there is an alternative for it. The
alternative is DEFINE_RUNTIME_DEV_PM_OPS() which is added in patch 4/6.

I don't think we need an immediate alternative to leave it deprecated, do we?

My point is, a user can still combine the macros in a way so that it
doesn't need to use the UNIVERSAL_DEV_PM_OPS.

Ok. I'll leave it deprecated in that patch then.

Cheers,
-Paul

>> #define UNIVERSAL_DEV_PM_OPS(name, suspend_fn, resume_fn, idle_fn)
 >> \
 >>   const struct dev_pm_ops __maybe_unused name = { \
 >>          SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
 >>  --

Kind regards
Uffe





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