[PATCH] clockevents: Shutdown detached clockevent device

[PATCH] clockevents: Shutdown detached clockevent device

[Viresh Kumar]

A clockevent device is marked DETACHED when it is replaced by another
clockevent device.

The device is shutdown properly for drivers that implement legacy
->set_mode() callback, as we call ->set_mode() for CLOCK_EVT_MODE_UNUSED
as well.

But for the new per-state callback interface, we skip shutting down the
device, as we thought its an internal state change. That wasn't correct.

The effect is that the device is left programmed in oneshot or periodic
mode.

Fall-back to 'case CLOCK_EVT_STATE_SHUTDOWN', to shutdown the device.

Fixes: bd624d75db21 ("clockevents: Introduce mode specific callbacks")
Reported-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---

Tested on Samsung's Arndale (Dual Cortex A15) board.

 kernel/time/clockevents.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 25d942d1da27..629be4e21e96 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -117,11 +117,7 @@ static int __clockevents_set_state(struct clock_event_device *dev,
 	/* Transition with new state-specific callbacks */
 	switch (state) {
 	case CLOCK_EVT_STATE_DETACHED:
-		/*
-		 * This is an internal state, which is guaranteed to go from
-		 * SHUTDOWN to DETACHED. No driver interaction required.
-		 */
-		return 0;
+		/* The clockevent device is getting replaced. Shut it down. */
 
 	case CLOCK_EVT_STATE_SHUTDOWN:
 		return dev->set_state_shutdown(dev);
-- 
2.3.0.rc0.44.ga94655d

[tip:timers/urgent] clockevents: Shutdown detached clockevent device

[tip-bot for Viresh Kumar]

Commit-ID:  149aabcc44e3e2c1f8fe4f0832be53d2db55b598
Gitweb:     http://git.kernel.org/tip/149aabcc44e3e2c1f8fe4f0832be53d2db55b598
Author:     Viresh Kumar <viresh.kumar@linaro.org>
AuthorDate: Fri, 10 Apr 2015 12:56:41 +0530
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 24 Apr 2015 21:01:48 +0200

clockevents: Shutdown detached clockevent device

A clockevent device is marked DETACHED when it is replaced by another
clockevent device.

The device is shutdown properly for drivers that implement legacy
->set_mode() callback, as we call ->set_mode() for CLOCK_EVT_MODE_UNUSED
as well.

But for the new per-state callback interface, we skip shutting down the
device, as we thought its an internal state change. That wasn't correct.

The effect is that the device is left programmed in oneshot or periodic
mode.

Fall-back to 'case CLOCK_EVT_STATE_SHUTDOWN', to shutdown the device.

Fixes: bd624d75db21 "clockevents: Introduce mode specific callbacks"
Reported-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/eef0a91c51b74d4e52c8e5a95eca27b5a0563f07.1428650683.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/time/clockevents.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 25d942d..629be4e 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -117,11 +117,7 @@ static int __clockevents_set_state(struct clock_event_device *dev,
 	/* Transition with new state-specific callbacks */
 	switch (state) {
 	case CLOCK_EVT_STATE_DETACHED:
-		/*
-		 * This is an internal state, which is guaranteed to go from
-		 * SHUTDOWN to DETACHED. No driver interaction required.
-		 */
-		return 0;
+		/* The clockevent device is getting replaced. Shut it down. */
 
 	case CLOCK_EVT_STATE_SHUTDOWN:
 		return dev->set_state_shutdown(dev);