diff options
| author | Arve Hjønnevåg <arve@android.com> | 2011-11-22 18:24:51 -0800 |
|---|---|---|
| committer | John Stultz <john.stultz@linaro.org> | 2011-11-22 19:25:56 -0800 |
| commit | 6a8943d9ec2567572fca25cf69ad45844d0141a3 (patch) | |
| tree | d14768e0747bd4b44fb00131c9c79713033c51c5 /drivers/rtc | |
| parent | c0afabd3d553c521e003779c127143ffde55a16f (diff) | |
| download | lwn-6a8943d9ec2567572fca25cf69ad45844d0141a3.tar.gz lwn-6a8943d9ec2567572fca25cf69ad45844d0141a3.zip | |
rtc: Fix some bugs that allowed accumulating time drift in suspend/resume
The current code checks if abs(delta_delta.tv_sec) is greater or
equal to two before it discards the old delta value, but this can
trigger at close to -1 seconds since -1.000000001 seconds is stored
as tv_sec -2 and tv_nsec 999999999 in a normalized timespec.
rtc_resume had an early return check if the rtc value had not changed
since rtc_suspend. This effectivly stops time for the duration of the
short sleep. Check if sleep_time is positive after all the adjustments
have been applied instead since this allows the old_system adjustment
in rtc_suspend to have an effect even for short sleep cycles.
CC: stable@kernel.org
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'drivers/rtc')
| -rw-r--r-- | drivers/rtc/class.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 01a7df5317c1..b82a1554cdc1 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -66,7 +66,7 @@ static int rtc_suspend(struct device *dev, pm_message_t mesg) */ delta = timespec_sub(old_system, old_rtc); delta_delta = timespec_sub(delta, old_delta); - if (abs(delta_delta.tv_sec) >= 2) { + if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) { /* * if delta_delta is too large, assume time correction * has occured and set old_delta to the current delta. @@ -100,9 +100,8 @@ static int rtc_resume(struct device *dev) rtc_tm_to_time(&tm, &new_rtc.tv_sec); new_rtc.tv_nsec = 0; - if (new_rtc.tv_sec <= old_rtc.tv_sec) { - if (new_rtc.tv_sec < old_rtc.tv_sec) - pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); + if (new_rtc.tv_sec < old_rtc.tv_sec) { + pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); return 0; } @@ -119,7 +118,8 @@ static int rtc_resume(struct device *dev) sleep_time = timespec_sub(sleep_time, timespec_sub(new_system, old_system)); - timekeeping_inject_sleeptime(&sleep_time); + if (sleep_time.tv_sec >= 0) + timekeeping_inject_sleeptime(&sleep_time); return 0; } |