[PATCH] cpuidle: undelaying cpuidle in dpm_{suspend|resume}()

From: Ikjoon Jang
Date: Tue Oct 29 2019 - 03:31:53 EST


cpuidle is paused only during dpm_suspend_noirq() ~ dpm_resume_noirq().
But some device drivers need random sized IOs in dpm_{suspend|resume}()
stage (e.g. re-downloading firmware in resume).
And with such a device, cpuidle's latencies could be critical to
response time of system suspend/resume.

To minimize those latencies, we could apply pm_qos to such device drivers,
but simply undelaying cpuidle from dpm_suspend_noirq() to dpm suspend()
seems no harm.
---
drivers/base/power/main.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 134a8af51511..5928dd2139e8 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -773,8 +773,6 @@ void dpm_resume_noirq(pm_message_t state)

resume_device_irqs();
device_wakeup_disarm_wake_irqs();
-
- cpuidle_resume();
}

static pm_callback_t dpm_subsys_resume_early_cb(struct device *dev,
@@ -1069,6 +1067,7 @@ void dpm_resume(pm_message_t state)

cpufreq_resume();
devfreq_resume();
+ cpuidle_resume();
trace_suspend_resume(TPS("dpm_resume"), state.event, false);
}

@@ -1411,8 +1410,6 @@ int dpm_suspend_noirq(pm_message_t state)
{
int ret;

- cpuidle_pause();
-
device_wakeup_arm_wake_irqs();
suspend_device_irqs();

@@ -1830,6 +1827,7 @@ int dpm_suspend(pm_message_t state)
trace_suspend_resume(TPS("dpm_suspend"), state.event, true);
might_sleep();

+ cpuidle_pause();
devfreq_suspend();
cpufreq_suspend();

--
2.24.0.rc0.303.g954a862665-goog