The patch titled
clocksource: save mult_orig in clocksource_disable()
has been added to the -mm tree. Its filename is
clocksource-save-mult_orig-in-clocksource_disable.patch
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------------------------------------------------------
Subject: clocksource: save mult_orig in clocksource_disable()
From: Magnus Damm <damm@xxxxxxxxxx>
Save clocksource mult_orig in clocksource_disable().
To fix the common case where ->enable() does not setup mult, make sure
mult_orig is saved in mult on disable.
Also add comments to explain why we do this.
Signed-off-by: Magnus Damm <damm@xxxxxxxxxx>
Acked-by: John Stultz <johnstul@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/clocksource.h | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff -puN include/linux/clocksource.h~clocksource-save-mult_orig-in-clocksource_disable include/linux/clocksource.h
--- a/include/linux/clocksource.h~clocksource-save-mult_orig-in-clocksource_disable
+++ a/include/linux/clocksource.h
@@ -293,7 +293,11 @@ static inline int clocksource_enable(str
if (cs->enable)
ret = cs->enable(cs);
- /* save mult_orig on enable */
+ /* The frequency may have changed while the clocksource
+ * was disabled. If so the code in ->enable() must update
+ * the mult value to reflect the new frequency. Make sure
+ * mult_orig follows this change.
+ */
cs->mult_orig = cs->mult;
return ret;
@@ -309,6 +313,12 @@ static inline int clocksource_enable(str
*/
static inline void clocksource_disable(struct clocksource *cs)
{
+ /* Save mult_orig in mult so clocksource_enable() can
+ * restore the value regardless if ->enable() updates
+ * the value of mult or not.
+ */
+ cs->mult = cs->mult_orig;
+
if (cs->disable)
cs->disable(cs);
}
_
Patches currently in -mm which might be from damm@xxxxxxxxxx are
linux-next.patch
clocksource-save-mult_orig-in-clocksource_disable.patch
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