From 226dd0193f9b8524789a86505ba05b1a74d916c1 Mon Sep 17 00:00:00 2001 From: Afzal Mohammed Date: Wed, 4 Jan 2012 10:52:31 +0530 Subject: [PATCH] [CPUFREQ] cpufreq:userspace: fix cpu_cur_freq updation CPU frequency is guranteed to be changed on notifier callback with CPUFREQ_POSTCHANGE. Notifier callback with CPUFREQ_PRECHANGE does not gurantee a change in frequency; after it, if cpufreq driver is unable to change CPU to new frequency. This results in wrong information being fed to user (if setting CPU frequency fails) upon doing like, cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed Hence in userspace governer update cpu_cur_freq only if notifier has been called with POSTCHANGE. Signed-off-by: Afzal Mohammed Signed-off-by: Dave Jones --- drivers/cpufreq/cpufreq_userspace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/cpufreq/cpufreq_userspace.c b/drivers/cpufreq/cpufreq_userspace.c index f231015904c0..bedac1aa9be3 100644 --- a/drivers/cpufreq/cpufreq_userspace.c +++ b/drivers/cpufreq/cpufreq_userspace.c @@ -47,9 +47,11 @@ userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val, if (!per_cpu(cpu_is_managed, freq->cpu)) return 0; - pr_debug("saving cpu_cur_freq of cpu %u to be %u kHz\n", - freq->cpu, freq->new); - per_cpu(cpu_cur_freq, freq->cpu) = freq->new; + if (val == CPUFREQ_POSTCHANGE) { + pr_debug("saving cpu_cur_freq of cpu %u to be %u kHz\n", + freq->cpu, freq->new); + per_cpu(cpu_cur_freq, freq->cpu) = freq->new; + } return 0; }