From mboxrd@z Thu Jan 1 00:00:00 1970 From: tglx@linutronix.de (Thomas Gleixner) Date: Fri, 16 Jan 2015 11:23:32 +0100 (CET) Subject: [RFC 2/2] clocksource: don't suspend/resume when unused In-Reply-To: <1421399874-29119-3-git-send-email-alexandre.belloni@free-electrons.com> References: <1421399874-29119-1-git-send-email-alexandre.belloni@free-electrons.com> <1421399874-29119-3-git-send-email-alexandre.belloni@free-electrons.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, 16 Jan 2015, Alexandre Belloni wrote: > There is no point in calling suspend/resume for unused > clocksources. > > Signed-off-by: Alexandre Belloni > --- > 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 920a4da58eb0..baea4e42ae90 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); This might be dangerous. If the clocksource has no enable/disable callbacks, but suspend/resume, then you might leave it enabled across suspend. Thanks, tglx