Re: [PATCH] rtc: cros-ec: return -ETIME when refused to set alarms in the past
From: Brian Norris <briannorris@chromium.org>
Date: 2018-02-26 18:37:33
Also in:
lkml
One last note: On Sun, Feb 25, 2018 at 04:18:02PM +0800, Jeffy Chen wrote:
quoted hunk ↗ jump to hunk
We have a check in __rtc_set_alarm() to return -ETIME when the alarm is in the past. Since accessing a Chrome OS EC based rtc is a slow operation, we should do that check again inside of the EC rtc driver's .set_alarm() callback. Signed-off-by: Jeffy Chen <redacted> --- drivers/rtc/rtc-cros-ec.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)diff --git a/drivers/rtc/rtc-cros-ec.c b/drivers/rtc/rtc-cros-ec.c index f0ea6899c731..ee0062e2d222 100644 --- a/drivers/rtc/rtc-cros-ec.c +++ b/drivers/rtc/rtc-cros-ec.c@@ -188,6 +188,10 @@ static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) if (alarm_time < 0 || alarm_time > U32_MAX) return -EINVAL; + /* Don't set an alarm in the past. */ + if ((u32)alarm_time <= current_time) + return -ETIME; + if (!alrm->enabled) { /* * If the alarm is being disabled, send an alarm@@ -196,11 +200,7 @@ static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) alarm_offset = EC_RTC_ALARM_CLEAR; cros_ec_rtc->saved_alarm = (u32)alarm_time; } else { - /* Don't set an alarm in the past. */ - if ((u32)alarm_time < current_time)
It's probably worth noting in the commit message that you're also fixing the case where 'alarm_time == current_time'; in the current driver source, it *looks* like you're setting a 0-second alarm. But in fact, 0 means EC_RTC_ALARM_CLEAR, which would disable the alarm. So you are (correctly) returning -ETIME in that case. Brian
- alarm_offset = EC_RTC_ALARM_CLEAR; - else - alarm_offset = (u32)alarm_time - current_time; + alarm_offset = (u32)alarm_time - current_time; } ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset); -- 2.11.0