On Monday, June 24, 2013 06:38:17 PM Viresh Kumar wrote:
On 24 June 2013 17:13, Rafael J. Wysocki rjw@sisk.pl wrote:
On Wednesday, June 19, 2013 02:23:07 PM Viresh Kumar wrote:
case CPUFREQ_POSTCHANGE:
WARN_ON(!transition_ongoing--);
Shouldn't we try to avoid going into the negative range here?
What about this patch? Find it attached to apply.
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 2d53f47..6624694 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -107,6 +107,9 @@ static void handle_update(struct work_struct *work); static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list); static struct srcu_notifier_head cpufreq_transition_notifier_list;
+/* Tracks status of transition */ +static int transition_ongoing;
static bool init_cpufreq_transition_notifier_list_called; static int __init init_cpufreq_transition_notifier_list(void) { @@ -264,6 +267,13 @@ void __cpufreq_notify_transition(struct cpufreq_policy *policy, switch (state) {
case CPUFREQ_PRECHANGE:
if (transition_ongoing) {
WARN(1, "In middle of another frequency transition\n");
return;
}
You can do
if (WARN(transition_ongoing, "<text>")) return;
and below analogously.
transition_ongoing++;
/* detect if the driver reported a value as "old frequency" * which is not equal to what the cpufreq core thinks is * "old frequency".
@@ -283,6 +293,13 @@ void __cpufreq_notify_transition(struct cpufreq_policy *policy, break;
case CPUFREQ_POSTCHANGE:
if (!transition_ongoing) {
WARN(1, "No frequency transition in progress\n");
return;
}
transition_ongoing--;
adjust_jiffies(CPUFREQ_POSTCHANGE, freqs); pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new, (unsigned long)freqs->cpu);
@@ -1458,6 +1475,8 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
if (cpufreq_disabled()) return -ENODEV;
if (transition_ongoing)
return -EBUSY; /* Make sure that target_freq is within supported range */ if (target_freq > policy->max)
Thanks, Rafael