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authorTero Kristo <tero.kristo@nokia.com>2011-02-24 17:19:23 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-06-03 10:34:42 +0900
commit4a1163dff6592dcee594b2bee597aafd749b93ee (patch)
tree381b1b08ad9eec1d17c7337ce45363e0b42871e1
parentf48e373ba0df22c98e0d8e9d8888d888b845e061 (diff)
downloadlinux-linaro-stable-4a1163dff6592dcee594b2bee597aafd749b93ee.tar.gz
cpuidle: menu: fixed wrapping timers at 4.294 seconds
commit 7467571f4480b273007517b26297c07154c73924 upstream. Cpuidle menu governor is using u32 as a temporary datatype for storing nanosecond values which wrap around at 4.294 seconds. This causes errors in predicted sleep times resulting in higher than should be C state selection and increased power consumption. This also breaks cpuidle state residency statistics. Signed-off-by: Tero Kristo <tero.kristo@nokia.com> Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/cpuidle/governors/menu.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index f508690eb958..c47f3d09c1ee 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -237,6 +237,7 @@ static int menu_select(struct cpuidle_device *dev)
unsigned int power_usage = -1;
int i;
int multiplier;
+ struct timespec t;
if (data->needs_update) {
menu_update(dev);
@@ -251,8 +252,9 @@ static int menu_select(struct cpuidle_device *dev)
return 0;
/* determine the expected residency time, round up */
+ t = ktime_to_timespec(tick_nohz_get_sleep_length());
data->expected_us =
- DIV_ROUND_UP((u32)ktime_to_ns(tick_nohz_get_sleep_length()), 1000);
+ t.tv_sec * USEC_PER_SEC + t.tv_nsec / NSEC_PER_USEC;
data->bucket = which_bucket(data->expected_us);