diff options
| author | Todd Poynor <toddpoynor@google.com> | 2012-08-07 17:14:52 -0700 |
|---|---|---|
| committer | Varun Wadekar <vwadekar@nvidia.com> | 2012-08-13 14:13:20 +0530 |
| commit | 564e6b431e9696d6b7186d120d563a74ae290092 (patch) | |
| tree | 4ed05fbc23e72e57575dcc53ca551f5b4f94098a /kernel | |
| parent | 559be66522421d65e323a2fae1016d968c1b9d12 (diff) | |
alarmtimer: implement minimum alarm interval for allowing suspend
alarmtimer suspend return -EBUSY if the next alarm will fire in less
than 2 seconds. This allows one RTC seconds tick to occur subsequent
to this check before the alarm wakeup time is set, ensuring the wakeup
time is still in the future (assuming the RTC does not tick one more
second prior to setting the alarm). If suspend is rejected, hold a
wakeup source for 2 seconds to process the alarm prior to reattempting
suspend.
Change-Id: If38e2568da0ea01dfee6e00323ce7e2c00f2f110
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/alarmtimer.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 01a0f5ff1990..0c079010527f 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -46,6 +46,8 @@ static struct alarm_base { static ktime_t freezer_delta; static DEFINE_SPINLOCK(freezer_delta_lock); +static struct wakeup_source *ws; + #ifdef CONFIG_RTC_CLASS /* rtc timer and device for setting alarm wakeups at suspend */ static struct rtc_timer rtctimer; @@ -246,6 +248,7 @@ static int alarmtimer_suspend(struct device *dev) unsigned long flags; struct rtc_device *rtc; int i; + int ret; spin_lock_irqsave(&freezer_delta_lock, flags); min = freezer_delta; @@ -275,8 +278,10 @@ static int alarmtimer_suspend(struct device *dev) if (min.tv64 == 0) return 0; - /* XXX - Should we enforce a minimum sleep time? */ - WARN_ON(min.tv64 < NSEC_PER_SEC); + if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) { + __pm_wakeup_event(ws, 2 * MSEC_PER_SEC); + return -EBUSY; + } /* Setup an rtc timer to fire that far in the future */ rtc_timer_cancel(rtc, &rtctimer); @@ -284,9 +289,11 @@ static int alarmtimer_suspend(struct device *dev) now = rtc_tm_to_ktime(tm); now = ktime_add(now, min); - rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0)); - - return 0; + /* Set alarm, if in the past reject suspend briefly to handle */ + ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0)); + if (ret < 0) + __pm_wakeup_event(ws, 1 * MSEC_PER_SEC); + return ret; } #else static int alarmtimer_suspend(struct device *dev) @@ -817,6 +824,7 @@ static int __init alarmtimer_init(void) error = PTR_ERR(pdev); goto out_drv; } + ws = wakeup_source_register("alarmtimer"); return 0; out_drv: |