cpuidle/ladder: add per cpu pm_qos_resume_latency consideration
Kernel or user may have special requirement on cpu response time, like
if a interrupt is pinned to a cpu, we don't want the cpu goes to deep
sleep. This patch can prevent this thing happen by consider per cpu
resume_latency setting in cpu sleep state selection in laddr governor.
Signed-off-by: Alex Shi <alex.shi@linaro.org>
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index 63bd5a4..d85bde8 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -18,6 +18,7 @@
#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/tick.h>
+#include <linux/cpu.h>
#include <asm/io.h>
#include <asm/uaccess.h>
@@ -69,8 +70,14 @@
{
struct ladder_device *ldev = this_cpu_ptr(&ladder_devices);
struct ladder_device_state *last_state;
+ struct device *device = get_cpu_device(dev->cpu);
int last_residency, last_idx = ldev->last_state_idx;
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
+ int resume_latency = dev_pm_qos_read_value(device);
+
+ /* resume_latency is 0 means no restriction */
+ if (resume_latency && resume_latency < latency_req)
+ latency_req = resume_latency;
/* Special case when user has set very strict latency requirement */
if (unlikely(latency_req == 0)) {