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

[Denis CIOCCA <denis.ciocca@st.com>]

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.

Thanks,
Denis


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