If a system does not provide a persistent_clock(), the time will be
updated on resume by rtc_resume(). With the addition of the non-stop
clocksources for suspend timing, those systems set the time on resume
in timekeeping_resume(), but may not provide a valid persistent_clock().
This results in the rtc_resume() logic thinking no one has set the time
and it then will over-write the suspend time again, which is not necessary
and only increases clock error.
So, fix this for rtc_resume().
Signed-off-by: Xunlei Pang <pang.xun...@linaro.org>
---
drivers/rtc/class.c | 2 +-
include/linux/timekeeping.h | 11 +++++++++++
kernel/time/timekeeping.c | 3 ++-
3 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 472a5ad..c8f35a5 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -102,7 +102,7 @@ static int rtc_resume(struct device *dev)
struct timespec64 sleep_time;
int err;
- if (has_persistent_clock())
+ if (rtc_resume_skip())
return 0;
rtc_hctosys_ret = -ENODEV;
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 9b63d13..6f3283b 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -238,6 +238,17 @@ extern void getnstime_raw_and_real(struct timespec *ts_raw,
*/
extern bool persistent_clock_exist;
extern int persistent_clock_is_local;
+extern bool suspendtime_found;
+
+#ifdef CONFIG_RTC_LIB
+/* Used by rtc_resume() */
+static inline bool rtc_resume_skip(void)
+{
+ return suspendtime_found;
+}
+#else
+static inline void rtc_resume_skip(void) { }
+#endif
static inline bool has_persistent_clock(void)
{
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 6a93185..586bb5c 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -65,6 +65,7 @@ int __read_mostly timekeeping_suspended;
/* Flag for if there is a persistent clock on this platform */
bool __read_mostly persistent_clock_exist = false;
+bool suspendtime_found;
static inline void tk_normalize_xtime(struct timekeeper *tk)
{
@@ -1178,8 +1179,8 @@ static void timekeeping_resume(void)
struct timespec64 ts_new, ts_delta;
struct timespec tmp;
cycle_t cycle_now, cycle_delta;
- bool suspendtime_found = false;
+ suspendtime_found = false;
read_persistent_clock(&tmp);
ts_new = timespec_to_timespec64(tmp);
--
1.9.1
--
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