[tip:timers/core] clockevents: Do not suspend/resume if unused

[tip-bot for Alexandre Belloni]

Commit-ID:  ac34ad27fc160b5bd31c731cdaaf6e1d1890ccb2
Gitweb:     http://git.kernel.org/tip/ac34ad27fc160b5bd31c731cdaaf6e1d1890ccb2
Author:     Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
AuthorDate: Fri, 16 Jan 2015 10:05:51 +0100
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Wed, 27 May 2015 01:03:38 +0200

clockevents: Do not suspend/resume if unused

There is no point in calling suspend/resume for unused clockevents as
they are already stopped and disabled.

This is really important for AT91 as the hardware is a trainwreck and
takes ages to synchronize.

Reported-by: Sylvain Rochet <sylvain.rochet@xxxxxxxxxxxx>
Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Cc: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
Cc: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
Cc: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1421399151-26800-1-git-send-email-alexandre.belloni@xxxxxxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
 kernel/time/clockevents.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 4922f1b..2a5c369 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -638,7 +638,7 @@ void clockevents_suspend(void)
 	struct clock_event_device *dev;
 
 	list_for_each_entry_reverse(dev, &clockevent_devices, list)
-		if (dev->suspend)
+		if (dev->suspend && dev->mode != CLOCK_EVT_MODE_UNUSED)
 			dev->suspend(dev);
 }
 
@@ -650,7 +650,7 @@ void clockevents_resume(void)
 	struct clock_event_device *dev;
 
 	list_for_each_entry(dev, &clockevent_devices, list)
-		if (dev->resume)
+		if (dev->resume && dev->mode != CLOCK_EVT_MODE_UNUSED)
 			dev->resume(dev);
 }
 
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