Re: iio_trigger_poll_chained stop and trig->use_count always equals to 1

[Lars-Peter Clausen <lars@metafoo.de>]

On 07/16/2013 03:26 PM, Denis CIOCCA wrote:
> Hi Lars,
> 
> thank you very much, now it works fine!
> 
> Only one thing:
> - In your patch I think there is a mistake on iio_trigger_poll_chained 
> function: generic_handle_irq should be replaced by handle_nested_irq.
> 
Yep, thanks. Will fix that in v2. Can you give v2 a try?

- Lars


> 
> 
> On Tuesday, July 16, 2013 12:28:06 PM Lars-Peter Clausen wrote:
>> On 07/16/2013 11:26 AM, Denis CIOCCA wrote:
>>> Hi all,
>>>
>>> I need your help to understanding my strange issue...
>>> The scenario is that:
>>>
>>> - I have one I2C device (microcontroller) that expose some sensors.
>>> - I wrote one driver that create one IIO device for each sensor.
>>> - There is only one trigger associated to all IIO devices, and one buffer
>>> for each device.
>>>
>>> When interrupt appear (DRDY of one or more sensors), the driver reads a
>>> mask from micro to understand how many sensors have new data. After that,
>>> the driver reads all new data from micro and save all data to one buffer.
>>> This is done in a threaded irq function.
>>>
>>> When iio_trigger_poll_chained is called, all data are saved to one common
>>> buffer, each iio_triggered_buffer_setup functions is called and can split
>>> and push their data to iio_buffer.
>>>
>>> The issue is that: after some samples (about 50:100) the
>>> iio_trigger_poll_chained doesn't call the iio_triggered_buffer_setup
>>> functions and trig->use_count is always equals to 1.
>>
>> Yea, there is a race condition. Try this patch:
>> http://www.spinics.net/lists/linux-iio/msg08710.html
>>
>> - Lars