When doing timekeeping_resume(), if the nonstop clocksource
wraps back, "cycle_delta" will miss the wrap time.
It's hard to determine the right CLOCKSOURCE_MASK(xxx) or
something to add code for inspecting such behavior, and we
don't have many existent nonstop clocksources, so just add
a comment to indicate that if have this flag set, people
are aware that this nonstop clocksource won't wrap back
during system suspend/resume.
Signed-off-by: Xunlei Pang <pang.xun...@linaro.org>
---
include/linux/clocksource.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index abcafaa..8680189 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -207,6 +207,11 @@ struct clocksource {
#define CLOCK_SOURCE_WATCHDOG 0x10
#define CLOCK_SOURCE_VALID_FOR_HRES 0x20
#define CLOCK_SOURCE_UNSTABLE 0x40
+
+/*
+ * When setting this flag, you're also supposed to mean that it doesn't
+ * wrap back during system suspend/resume. See timekeeping_resume().
+ */
#define CLOCK_SOURCE_SUSPEND_NONSTOP 0x80
#define CLOCK_SOURCE_RESELECT 0x100
--
1.9.1
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