diff options
Diffstat (limited to 'drivers/rtc/interface.c')
| -rw-r--r-- | drivers/rtc/interface.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index dc741ba29fa3..b8b298efd9a9 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -443,6 +443,29 @@ static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) else err = rtc->ops->set_alarm(rtc->dev.parent, alarm); + /* + * Check for potential race described above. If the waiting for next + * second, and the second just ticked since the check above, either + * + * 1) It ticked after the alarm was set, and an alarm irq should be + * generated. + * + * 2) It ticked before the alarm was set, and alarm irq most likely will + * not be generated. + * + * While we cannot easily check for which of these two scenarios we + * are in, we can return -ETIME to signal that the timer has already + * expired, which is true in both cases. + */ + if ((scheduled - now) <= 1) { + err = __rtc_read_time(rtc, &tm); + if (err) + return err; + now = rtc_tm_to_time64(&tm); + if (scheduled <= now) + return -ETIME; + } + trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err); return err; } @@ -594,6 +617,10 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) rtc->uie_rtctimer.node.expires = ktime_add(now, onesec); rtc->uie_rtctimer.period = ktime_set(1, 0); err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer); + if (!err && rtc->ops && rtc->ops->alarm_irq_enable) + err = rtc->ops->alarm_irq_enable(rtc->dev.parent, 1); + if (err) + goto out; } else { rtc_timer_remove(rtc, &rtc->uie_rtctimer); } |