On Friday, July 26, 2013 10:33:21 AM Lukasz Majewski wrote:
On Fri, 26 Jul 2013 12:47:15 +0530 Viresh Kumar wrote,
On 25 July 2013 22:03, Lukasz Majewski l.majewski@samsung.com wrote:
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
/*********************************************************************
BOOST *
*********************************************************************/ +static int cpufreq_boost_set_sw(int state) +{
struct cpufreq_frequency_table *freq_table;struct cpufreq_policy *policy;int ret = -EINVAL;list_for_each_entry(policy, &cpufreq_policy_list,policy_list) {
freq_table =cpufreq_frequency_get_table(policy->cpu);
if (freq_table) {ret =cpufreq_frequency_table_cpuinfo(policy,
freq_table);if (!ret) {policy->user_policy.max =policy->max;
__cpufreq_governor(policy,CPUFREQ_GOV_LIMITS);
}}}return ret;+}
+int cpufreq_boost_trigger_state(int state) +{
unsigned long flags;int ret = 0;if (cpufreq_driver->boost_enabled == state)return 0;write_lock_irqsave(&cpufreq_driver_lock, flags);cpufreq_driver->boost_enabled = state;write_unlock_irqrestore(&cpufreq_driver_lock, flags);^^^^^^^^^^^^^^^^^^^^ [*]Not sure if we should leave the lock at this point of time, as we haven't enabled boost until now.
The problem here is with the cpufreq_driver->set_boost() call.
I tried to avoid acquiring lock at one function and release it at another (in this case cpufreq_boost_set_sw), especially since the __cpufreq_governor() acquires its own lock - good place for deadlock.
Is it OK for you to grab lock at one function (cpufreq_boost_trigger_state()) and then at other function (cpufreq_boost_set_sw) release it before calling __cpufreq_governor() and grab it again after its completion?
It generally is better to avoid doing that, although it is not unheard of.
Thanks, Rafael