On Thu, Dec 17, 2015 at 5:00 PM, Pandruvada, Srinivas
[off-list ref] wrote:

Hi Andy,

As per Nish these patches are impacting sensors on Yoga.
https://lkml.org/lkml/2015/11/30/441

To be clear, without that series, the touchpad and touchscreen on the
Yoga 900 don't work at all. So they are necessary for functioning. I
don't know (I will test it now), if removing the series makes the IIO
sensors work properly in /dev/.

-Nish

On Thu, 2015-12-17 at 16:51 -0800, Srinivas Pandruvada wrote:

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On Thu, 2015-12-17 at 15:38 -0800, Nish Aravamudan wrote:

quoted

[Starting a new thread from https://lkml.org/lkml/2015/12/15/663,
as
now my laptop is displaying values in the sysfs *raw* files.]

So I'm trying to understand exactly how the hid-sensor-accel-3d
driver works.

If I turn up debugging, when I `cat
/sys/bus/iio/devices/device*/*raw*`, I see "iio iio:device3:
accel_3d_proc_event" and I think that means that
hid_sensor_push_data() is getting called.

But read()'s on /dev/iio:device3 never produces anything, which is
what iio-sensor-proxy uses to translate events to dbus.

Is it expected that the dev-node is "silent"? Just trying to
understand if an extension to the driver to support a chardev based
output is appropriate, or if iio-sensor-proxy needs to be changed
to
handle this device.

You are saying there is some regression. This used to work and now it
doesn't work. Is raw values are displayed correctly, when you do
"cat"?
If cat of raw values is working then power on of sensors is working.

Turn on HID debug prints. If it is regression we can do git bisect.
Any ACPI or PM changes can break this. Usually there will be GPIOs
which will be involved in power on, where ACPI comes into play. This
will be done by i2c-hid. There are some prints in i2c-hid which can
be
enabled also.

Thanks,
Srinivas

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