Hi,
On 16-04-18 00:34, Srinivas Pandruvada wrote:
On Sun, 2018-04-15 at 15:58 +0100, Jonathan Cameron wrote:
On Sat, 14 Apr 2018 17:09:09 +0200
Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
hid_sensor_set_power_work() powers the sensors back up after a
resume
based on the user_requested_state atomic_t.
But hid_sensor_power_state() treats this as a boolean flag, leading
to
the following problematic scenario:
1) Some app starts using the iio-sensor in buffered / triggered
mode,
hid_sensor_data_rdy_trigger_set_state(true) gets called, setting
user_requested_state to 1.
2) Something directly accesses a _raw value through sysfs, leading
to a call to hid_sensor_power_state(true) followed by
hid_sensor_power_state(false) call, this sets
user_requested_state
to 1 followed by setting it to 0.
3) Suspend/resume the machine, hid_sensor_set_power_work() now does
NOT power the sensor back up because user_requested_state
(wrongly)
is 0. Which stops the app using the sensor in buffered mode from
receiving any new values.
This commit changes user_requested_state to a counter tracking how
many
times hid_sensor_power_state(true) was called instead, fixing this.
Cc: Bastien Nocera <hadess@xxxxxxxxxx>
Cc: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
Which App is doing like this?
No app, just something I noticed while manually testing the
accelerometer while iio-sensor-proxy was also active.
Regards,
Hans
Thanks,
Srinivas
Looks sensible to me.
I'll give it a few days at least though for others to comment.
Thanks,
Jonathan
---
drivers/iio/common/hid-sensors/hid-sensor-trigger.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/common/hid-sensors/hid-sensor-trigger.c
b/drivers/iio/common/hid-sensors/hid-sensor-trigger.c
index cfb6588565ba..4905a997a7ec 100644
--- a/drivers/iio/common/hid-sensors/hid-sensor-trigger.c
+++ b/drivers/iio/common/hid-sensors/hid-sensor-trigger.c
@@ -178,14 +178,14 @@ 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 (atomic_add_unless(&st->runtime_pm_enable, 1, 1))
pm_runtime_enable(&st->pdev->dev);
- if (state)
+ if (state) {
+ atomic_inc(&st->user_requested_state);
ret = pm_runtime_get_sync(&st->pdev->dev);
- else {
+ } else {
+ atomic_dec(&st->user_requested_state);
pm_runtime_mark_last_busy(&st->pdev->dev);
pm_runtime_use_autosuspend(&st->pdev->dev);
ret = pm_runtime_put_autosuspend(&st->pdev->dev);
--
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