Re: [PATCH] iio: imu: st_lsm6dsx: no answer after some iio_generic_buffer test cycles

[Philippe De Muyter <phdm@macq.eu>]

Hello Lorenzo,

On Mon, Feb 13, 2023 at 10:19:57AM +0100, Philippe De Muyter wrote:
> I have a bug, with our without the patch : frequently
> my test, using a loop around iio-generic-buffer, blocks on the poll syscall.
> No value comes anymore.  This happens both with the gyro as with the accel
> component.
> 
> More info follows.

Here is the way I test :

 # iio/lsiio 
 Device 001: ism330dlc_gyro
 Device 002: ism330dlc_accel
 Device 000: ina3221x
 # for axis in x y z; do echo 1 >/sys/bus/iio/devices/iio\:device1/scan_elements/in_anglvel_${axis}_en; done
 # echo 416 > /sys/bus/iio/devices/iio\:device1/sampling_frequency
 # while true; do  sudo iio/iio_generic_buffer -n ism330dlc_gyro -g -c 6 -a; sleep 2; done
 iio device number being used is 1
 trigger-less mode selected
 Auto-channels selected but some channels are already activated in sysfs
 Proceeding without activating any channels
 0.002291 -0.073762 0.033139 
 0.003971 -0.075289 0.035583 
 0.003971 -0.076969 0.036194 
 0.004123 -0.074220 0.037110 
 0.003207 -0.074678 0.034667 
 0.002596 -0.073456 0.035277 
 iio device number being used is 1
 trigger-less mode selected
 Auto-channels selected but some channels are already activated in sysfs
 Proceeding without activating any channels
 0.002138 -0.074067 0.034819 
 0.003512 -0.075442 0.034819 
 0.001985 -0.074373 0.035430 
 0.002902 -0.074373 0.035888 
 0.002138 -0.074220 0.036346 
 0.003360 -0.076053 0.035277

After a quick time, iio_generic_buffer gets blocked in the poll syscall.
Hitting 'CTRL-C' kills the iio_generic_buffer process, and the next one
then receives values.

This happens with both gyro and accel.

Do you encounter the same problem ?

My kernel is actually a 4.9 one with a backport of iio core infrastructure
and iio/imu/st_lsm6dsx of 6.2, but I could have missed something important.

Best regards

Philippe