1 files changed, 21 insertions, 1 deletions

diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 5a40d14daa9f..1219be4fb42e 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -288,7 +288,20 @@ static inline cycle_t clocksource_read(struct clocksource *cs)
  */
 static inline int clocksource_enable(struct clocksource *cs)
 {
-        return cs->enable ? cs->enable(cs) : 0;
+        int ret = 0;
+
+        if (cs->enable)
+                ret = cs->enable(cs);
+
+        /*
+         * 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;
 }
 
 /**
@@ -301,6 +314,13 @@ static inline int clocksource_enable(struct clocksource *cs)
  */
 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);
 }