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authorAfzal Mohammed <afzal@ti.com>2012-01-04 10:52:46 +0530
committerDave Jones <davej@redhat.com>2012-01-06 10:10:53 -0500
commitd08de0c19c3fc5b9cf557ce3b42795d036ad5da9 (patch)
tree30a8c983a35ae8caea55e4d741f291ada66f8965 /drivers/cpufreq
parent226dd0193f9b8524789a86505ba05b1a74d916c1 (diff)
downloadlinux-d08de0c19c3fc5b9cf557ce3b42795d036ad5da9.tar.bz2
[CPUFREQ] update lpj only if frequency has changed
During scaling up of cpu frequency, loops_per_jiffy is updated upon invoking PRECHANGE notifier. If setting to new frequency fails in cpufreq driver, lpj is left at incorrect value. Hence update lpj only if cpu frequency is changed, i.e. upon invoking POSTCHANGE notifier. Penalty would be that during time period between changing cpu frequency & invocation of POSTCHANGE notifier, udelay(x) may not gurantee minimal delay of 'x' us for frequency scaling up operation. Perhaps a better solution would be to define CPUFREQ_ABORTCHANGE & handle accordingly, but then it would be more intrusive (using ABORTCHANGE may help drivers also; if any has registered notifier and expect POST for a PRECHANGE, their needs can be taken care using ABORT) Signed-off-by: Afzal Mohammed <afzal@ti.com> Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 987a165ede26..2f5801adc739 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -204,8 +204,7 @@ static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
pr_debug("saving %lu as reference value for loops_per_jiffy; "
"freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
}
- if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
- (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
+ if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) ||
(val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
ci->new);