On Fri, 16 Jan 2015, Alexandre Belloni wrote:
> There is no point in calling suspend/resume for unused
> clocksources.
That's true, but ....
> Signed-off-by: Alexandre Belloni <alexandre.bell...@free-electrons.com>
> ---
> kernel/time/clocksource.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> index 03cfc5a08e3b..da65b3b73a86 100644
> --- a/kernel/time/clocksource.c
> +++ b/kernel/time/clocksource.c
> @@ -493,7 +493,7 @@ void clocksource_suspend(void)
> struct clocksource *cs;
>
> list_for_each_entry_reverse(cs, &clocksource_list, list)
> - if (cs->suspend)
> + if (cs->suspend && (cs->flags & CLOCK_SOURCE_USED))
> cs->suspend(cs);
> }
>
> @@ -505,7 +505,7 @@ void clocksource_resume(void)
> struct clocksource *cs;
>
> list_for_each_entry(cs, &clocksource_list, list)
> - if (cs->resume)
> + if (cs->resume && (cs->flags & CLOCK_SOURCE_USED))
> cs->resume(cs);
I had a deeper look at the clocksources which have a resume
callback. We have implementations, which rely on the resume callback
being called unconditionally. e.g.: arch/x86/kernel/hpet.c. And there
are a few others which have extra PM code in the suspend/resume path
independent of the fact whether the clocksource is enabled or not.
So we really need to make this opt-in with a per clocksource flag.
Thanks,
tglx
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