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authorTero Kristo <tero.kristo@nokia.com>2011-02-24 17:19:23 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-06-23 15:24:04 -0700
commitaf73c7b853bbfd629e1cf02bb6df1c78fd4f1bd1 (patch)
tree1bcc1cb3160ad52d3507e546cbcb9a1f0e163d66
parentc8b6153da29826fb498c452a185e96322fdc4946 (diff)
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 f8e57c6303f2..053743780baa 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -185,6 +185,7 @@ static int menu_select(struct cpuidle_device *dev)
int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY);
int i;
int multiplier;
+ struct timespec t;
if (data->needs_update) {
menu_update(dev);
@@ -199,8 +200,9 @@ 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);