[PATCH/RFC 1/6] alarmtimer: Postpone wake-up source registration until really available

Geert Uytterhoeven
2017-02-20T20:33:24Z

Currently the alarmtimer registers a wake-up source unconditionally,
regardless of the system having a (wake-up capable) RTC or not.
To fix this, postpone registration until a wake-up capable RTC device is
added.

After this, the alarmtimer no longer shows up in
/sys/kernel/debug/wakeup_sources, unless it is available for real.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
kernel/time/alarmtimer.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index e6dc9a538efa2116..5e0ce78607da5b5d 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -82,6 +82,7 @@ static int alarmtimer_rtc_add_device(struct device *dev,
{
unsigned long flags;
struct rtc_device *rtc = to_rtc_device(dev);
+ struct wakeup_source *__ws;

if (rtcdev)
return -EBUSY;
@@ -91,13 +92,20 @@ static int alarmtimer_rtc_add_device(struct device *dev,
if (!device_may_wakeup(rtc->dev.parent))
return -1;

+ __ws = wakeup_source_register("alarmtimer");
+
spin_lock_irqsave(&rtcdev_lock, flags);
if (!rtcdev) {
rtcdev = rtc;
/* hold a reference so it doesn't go away */
get_device(dev);
+ ws = __ws;
+ __ws = NULL;
}
spin_unlock_irqrestore(&rtcdev_lock, flags);
+
+ wakeup_source_unregister(__ws);
+
return 0;
}

@@ -908,7 +916,6 @@ static int __init alarmtimer_init(void)
error = PTR_ERR(pdev);
goto out_drv;
}
- ws = wakeup_source_register("alarmtimer");
return 0;

out_drv:
--
2.7.4