[PATCH] iio: imu: kmx61: reject duplicate event disable

[PATCH] iio: imu: kmx61: reject duplicate event disable

[Jiale Yao]

The IIO core does not filter duplicate writes to the event enable
attribute. kmx61_write_event_config() already ignores repeated enable
requests, but a repeated disable request still calls
kmx61_set_power_state(data, false, KMX61_ACC), dropping a runtime PM
reference that was not acquired for this request. This can underflow the
runtime PM usage count and trigger a "Runtime PM usage count underflow"
warning.

Return early when the requested state already matches ev_enable_state.

Signed-off-by: Jiale Yao <yaojiale02@163.com>
---
 drivers/iio/imu/kmx61.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/imu/kmx61.c b/drivers/iio/imu/kmx61.c
index c288437d53ea..a4962b88ef58 100644
--- a/drivers/iio/imu/kmx61.c
+++ b/drivers/iio/imu/kmx61.c
@@ -939,7 +939,7 @@ static int kmx61_write_event_config(struct iio_dev *indio_dev,
 	struct kmx61_data *data = kmx61_get_data(indio_dev);
 	int ret = 0;
 
-	if (state && data->ev_enable_state)
+	if (state == data->ev_enable_state)
 		return 0;
 
 	guard(mutex)(&data->lock);
-- 
2.34.1

Re: [PATCH] iio: imu: kmx61: reject duplicate event disable

[Andy Shevchenko]

On Fri, Sep 25, 2026 at 10:10:05PM +0800, Jiale Yao wrote:
> The IIO core does not filter duplicate writes to the event enable
> attribute. kmx61_write_event_config() already ignores repeated enable
> requests, but a repeated disable request still calls
> kmx61_set_power_state(data, false, KMX61_ACC), dropping a runtime PM
> reference that was not acquired for this request. This can underflow the
> runtime PM usage count and trigger a "Runtime PM usage count underflow"
> warning.
> 
> Return early when the requested state already matches ev_enable_state.

Same comments as per previous patches of the same topic.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] iio: imu: kmx61: reject duplicate event disable

[Jonathan Cameron]

On Fri, 25 Sep 2026 17:18:44 +0300
Andy Shevchenko <andriy.shevchenko@intel.com> wrote:

> On Fri, Sep 25, 2026 at 10:10:05PM +0800, Jiale Yao wrote:
> > The IIO core does not filter duplicate writes to the event enable
> > attribute. kmx61_write_event_config() already ignores repeated enable
> > requests, but a repeated disable request still calls
> > kmx61_set_power_state(data, false, KMX61_ACC), dropping a runtime PM
> > reference that was not acquired for this request. This can underflow the
> > runtime PM usage count and trigger a "Runtime PM usage count underflow"
> > warning.
> > 
> > Return early when the requested state already matches ev_enable_state.  
> 
> Same comments as per previous patches of the same topic.
> 
Fixes tag needed.

Re:Re: [PATCH] iio: imu: kmx61: reject duplicate event disable

[jiale yao]

At 2026-09-28 01:20:31, "Jonathan Cameron" <jic23@kernel.org> wrote:
>On Fri, 25 Sep 2026 17:18:44 +0300
>Andy Shevchenko <andriy.shevchenko@intel.com> wrote:
>
>> On Fri, Sep 25, 2026 at 10:10:05PM +0800, Jiale Yao wrote:
>> > The IIO core does not filter duplicate writes to the event enable
>> > attribute. kmx61_write_event_config() already ignores repeated enable
>> > requests, but a repeated disable request still calls
>> > kmx61_set_power_state(data, false, KMX61_ACC), dropping a runtime PM
>> > reference that was not acquired for this request. This can underflow the
>> > runtime PM usage count and trigger a "Runtime PM usage count underflow"
>> > warning.
>> > 
>> > Return early when the requested state already matches ev_enable_state.  
>> 
>> Same comments as per previous patches of the same topic.
>> 
>Fixes tag needed.

Fixes: fd3ae7a9f21c ("iio: imu: kmx61: Add support for any motion trigger")

Re: [PATCH] iio: imu: kmx61: reject duplicate event disable

[Jonathan Cameron]

On Mon, 28 Sep 2026 16:30:02 +0800 (CST)
"jiale yao" <19888972804@163.com> wrote:

> At 2026-09-28 01:20:31, "Jonathan Cameron" <jic23@kernel.org> wrote:
> >On Fri, 25 Sep 2026 17:18:44 +0300
> >Andy Shevchenko <andriy.shevchenko@intel.com> wrote:
> >  
> >> On Fri, Sep 25, 2026 at 10:10:05PM +0800, Jiale Yao wrote:  
> >> > The IIO core does not filter duplicate writes to the event enable
> >> > attribute. kmx61_write_event_config() already ignores repeated enable
> >> > requests, but a repeated disable request still calls
> >> > kmx61_set_power_state(data, false, KMX61_ACC), dropping a runtime PM
> >> > reference that was not acquired for this request. This can underflow the
> >> > runtime PM usage count and trigger a "Runtime PM usage count underflow"
> >> > warning.
> >> > 
> >> > Return early when the requested state already matches ev_enable_state.    
> >> 
> >> Same comments as per previous patches of the same topic.
> >>   
> >Fixes tag needed.  
> 
> Fixes: fd3ae7a9f21c ("iio: imu: kmx61: Add support for any motion trigger")

Applied to the fixes-togreg branch of iio.git and marked for stable.

Thanks

Jonathan