5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nikhil Gautam [ Upstream commit 579c049b4cb6fc72ce2c505fc5334540be0efcd3 ] The IIO core does not filter duplicate writes to the event enable attribute, so writing the same value twice invokes write_event_config() twice. Enabling twice leaks a runtime PM reference, preventing the device from ever suspending again; disabling twice underflows the usage count and triggers a "Runtime PM usage count underflow" warning. Bail out early when the requested state matches the current state. While at it, switch to pm_runtime_resume_and_get() so a failed resume is propagated to userspace instead of silently marking the event enabled. Fixes: 97d642e23037c ("iio: light: Add a driver for Sharp GP2AP002x00F") Signed-off-by: Nikhil Gautam Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- drivers/iio/light/gp2ap002.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/iio/light/gp2ap002.c b/drivers/iio/light/gp2ap002.c index 7725d0ef8a721..3d1ab38799c43 100644 --- a/drivers/iio/light/gp2ap002.c +++ b/drivers/iio/light/gp2ap002.c @@ -343,6 +343,10 @@ static int gp2ap002_write_event_config(struct iio_dev *indio_dev, int state) { struct gp2ap002 *gp2ap002 = iio_priv(indio_dev); + int ret; + + if (state == gp2ap002->enabled) + return 0; if (state) { /* @@ -350,14 +354,17 @@ static int gp2ap002_write_event_config(struct iio_dev *indio_dev, * already) and reintialize the sensor by using runtime_pm * callbacks. */ - pm_runtime_get_sync(gp2ap002->dev); - gp2ap002->enabled = true; + ret = pm_runtime_resume_and_get(gp2ap002->dev); + if (ret) + return ret; + } else { pm_runtime_mark_last_busy(gp2ap002->dev); pm_runtime_put_autosuspend(gp2ap002->dev); - gp2ap002->enabled = false; } + gp2ap002->enabled = state; + return 0; } -- 2.53.0