cpufreq: interactive: avoid underflow on active time calculation
Check for idle time delta less than elapsed time delta, avoid
underflow computing active time.
Change-Id: I3e4c6ef1ad794eec49ed379c0c50fa727fd6ad28
Signed-off-by: Minsung Kim <ms925.kim@samsung.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index b4d12b2..7303f50 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -325,7 +325,12 @@
now_idle = get_cpu_idle_time(cpu, &now);
delta_idle = (unsigned int)(now_idle - pcpu->time_in_idle);
delta_time = (unsigned int)(now - pcpu->time_in_idle_timestamp);
- active_time = delta_time - delta_idle;
+
+ if (delta_time <= delta_idle)
+ active_time = 0;
+ else
+ active_time = delta_time - delta_idle;
+
pcpu->cputime_speedadj += active_time * pcpu->policy->cur;
pcpu->time_in_idle = now_idle;