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| author | Magnus Damm <magnus.damm@gmail.com> | 2009-07-28 14:09:55 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-07-31 14:12:36 +0200 |
| commit | c7121843685de2bf7f3afd3ae1d6a146010bf1fc (patch) | |
| tree | f3a098159b8463386cd6d55b6272b6604bfbb9ce /include/linux/clocksource.h | |
| parent | 4be3bd7849165e7efa6b0b35a23d6a3598d97465 (diff) | |
| download | linux-c7121843685de2bf7f3afd3ae1d6a146010bf1fc.tar.gz linux-c7121843685de2bf7f3afd3ae1d6a146010bf1fc.tar.bz2 linux-c7121843685de2bf7f3afd3ae1d6a146010bf1fc.zip | |
clocksource: Save mult_orig in clocksource_disable()
To fix the common case where ->enable() does not set up
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@igel.co.jp>
Cc: johnstul@us.ibm.com
Cc: lethal@linux-sh.org
Cc: akpm@linux-foundation.org
LKML-Reference: <20090618152432.10136.9932.sendpatchset@rx1.opensource.se>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/linux/clocksource.h')
| -rw-r--r-- | include/linux/clocksource.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index c56457c8334e..1219be4fb42e 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -293,7 +293,12 @@ static inline int clocksource_enable(struct clocksource *cs) 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 +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); } |