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

Andreas Kemnade andreas at kemnade.info
Tue Apr 17 07:24:30 CEST 2018


On Mon, 16 Apr 2018 12:26:23 +0200
"H. Nikolaus Schaller" <hns at goldelico.com> wrote:

> 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?

while true ; do echo X: $(<in_accel_x_raw ) Y: $(<in_accel_y_raw) Z: $(<in_accel_z_raw); done

does not work sluggish. So the accelerometer driver is not guilthy.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
URL: <http://lists.goldelico.com/pipermail/letux-kernel/attachments/20180417/50b81177/attachment.asc>

More information about the Letux-kernel mailing list