[PATCH v1] Fix suspend/resume delay

[PATCH v1] Fix suspend/resume delay

[Srinivas Pandruvada]

v1
Simplified patch to match user request before runtime resume.
This is very similar to USB xhci where runtime resume function is checking
any outstanding XHCI request to wake up before proceeding to resume.

v0
Optimize using Linux PM notifiers to get notification of PM states

Srinivas Pandruvada (1):
  hid-sensor: Fix suspend/resume delay

 drivers/iio/common/hid-sensors/hid-sensor-trigger.c | 11 ++++++++++-
 include/linux/hid-sensor-hub.h                      |  1 +
 2 files changed, 11 insertions(+), 1 deletion(-)

-- 
2.1.4

[PATCH v1] hid-sensor: Fix suspend/resume delay

[Srinivas Pandruvada]

By default all the sensors are runtime suspended state (lowest power
state). During Linux suspend process, all the run time suspended
devices are resumed and then suspended. This caused all sensors to
power up and introduced delay in suspend time, when we introduced
runtime PM for HID sensors. The opposite process happens during resume
process.
To fix this, we do powerup process of the sensors only when the request
is issued from user (raw or tiggerred). In this way when runtime,
resume calls for powerup it will simply return as this will not match
user requested state.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/iio/common/hid-sensors/hid-sensor-trigger.c | 11 ++++++++++-
 include/linux/hid-sensor-hub.h                      |  1 +
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/common/hid-sensors/hid-sensor-trigger.c b/drivers/iio/common/hid-sensors/hid-sensor-trigger.c
index 610fc98..5955110 100644
--- a/drivers/iio/common/hid-sensors/hid-sensor-trigger.c
+++ b/drivers/iio/common/hid-sensors/hid-sensor-trigger.c
@@ -36,6 +36,8 @@ static int _hid_sensor_power_state(struct hid_sensor_common *st, bool state)
 	s32 poll_value = 0;
 
 	if (state) {
+		if (!atomic_read(&st->user_requested_state))
+			return 0;
 		if (sensor_hub_device_open(st->hsdev))
 			return -EIO;
 
@@ -52,8 +54,12 @@ static int _hid_sensor_power_state(struct hid_sensor_common *st, bool state)
 
 		poll_value = hid_sensor_read_poll_value(st);
 	} else {
-		if (!atomic_dec_and_test(&st->data_ready))
+		int val;
+
+		val = atomic_dec_if_positive(&st->data_ready);
+		if (val < 0)
 			return 0;
+
 		sensor_hub_device_close(st->hsdev);
 		state_val = hid_sensor_get_usage_index(st->hsdev,
 			st->power_state.report_id,
@@ -92,9 +98,11 @@ EXPORT_SYMBOL(hid_sensor_power_state);
 
 int hid_sensor_power_state(struct hid_sensor_common *st, bool state)
 {
+
 #ifdef CONFIG_PM
 	int ret;
 
+	atomic_set(&st->user_requested_state, state);
 	if (state)
 		ret = pm_runtime_get_sync(&st->pdev->dev);
 	else {
@@ -109,6 +117,7 @@ int hid_sensor_power_state(struct hid_sensor_common *st, bool state)
 
  	return 0;
 #else
+	atomic_set(&st->user_requested_state, state);
 	return _hid_sensor_power_state(st, state);
 #endif
 }
diff --git a/include/linux/hid-sensor-hub.h b/include/linux/hid-sensor-hub.h
index 0042bf3..c02b5ce 100644
--- a/include/linux/hid-sensor-hub.h
+++ b/include/linux/hid-sensor-hub.h
@@ -230,6 +230,7 @@ struct hid_sensor_common {
 	struct platform_device *pdev;
 	unsigned usage_id;
 	atomic_t data_ready;
+	atomic_t user_requested_state;
 	struct iio_trigger *trigger;
 	struct hid_sensor_hub_attribute_info poll;
 	struct hid_sensor_hub_attribute_info report_state;
-- 
2.1.4

RE: [PATCH v1] hid-sensor: Fix suspend/resume delay

[Brown, Len]

This regression increased the resume time on my Dell XPS11 laptop by 8 seco=
nds.
This patch makes that regression go away.

I assume that this is targeted for .stable?

thanks,
Tested-by: Len Brown <len.brown@intel.com>

Re: [PATCH v1] hid-sensor: Fix suspend/resume delay

[Jonathan Cameron]

On 02/06/15 07:21, Brown, Len wrote:
> This regression increased the resume time on my Dell XPS11 laptop by 8 seconds.
> This patch makes that regression go away.
> 
> I assume that this is targeted for .stable?
> 
> thanks,
> Tested-by: Len Brown <len.brown@intel.com>
> 
Applied to the fixes-togreg branch of iio.git which will get pushed out
when I am back on a network.  Thanks for providing this number Len.
I've added a note to the commit to make it clear that the timing regression
was substantial and marked it for stable.

Thanks,

Jonathan