[Letux-kernel] evtest /dev/input/accel

H. Nikolaus Schaller hns at goldelico.com
Mon Apr 16 12:26:23 CEST 2018


Hi,
I noticed a strange effect.

If I run

evtest /dev/input/accel | head -20

there is a report of the range and the current value of
the accelerometer.

But it is "history". Which means that if I
run this, then rotate the device and run again,
I will get the old (unrotated) values. Only if
I run once more, I get the new ones.

So this might also have an influence why QtMaze
seems sluggish, i.e. has a noticeable delay.

It is unclear if this is an effect of the
kernel input layer or the iio subsystem. Or
the iio-bridge (maybe it gets buffered values
where it should trigger a new read request).

Has anyone seen this as well?

BR,
Nikolaus



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