linux-kernel - Re: Issues with Lenovo Yoga 900 IIO devices (accelerometer, etc.)

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Message-ID: <CAKv63uvEKOycY2pPCRwVXvYR1yj8SbBaPJyw41_7mc4Vnftkew@mail.gmail.com>
Date:	Wed, 16 Dec 2015 23:22:56 +0100
From:	Crt Mori <cmo@...exis.com>
To:	Nish Aravamudan <nish.aravamudan@...il.com>
Cc:	Daniel Baluta <daniel.baluta@...il.com>,
	Jonathan Cameron <jic23@...nel.org>,
	Hartmut Knaack <knaack.h@....de>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Peter Meerwald <pmeerw@...erw.net>,
	"linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Issues with Lenovo Yoga 900 IIO devices (accelerometer, etc.)

On 16 December 2015 at 22:41, Nish Aravamudan <nish.aravamudan@...il.com> wrote:
> Hi Daniel,
>
> On Wed, Dec 16, 2015 at 1:43 AM, Daniel Baluta <daniel.baluta@...il.com> wrote:
>> On Tue, Dec 15, 2015 at 9:19 PM, Nish Aravamudan
>> <nish.aravamudan@...il.com> wrote:
>>> So, I apologize in advance for this relatively vague report, but I'm fairly sure
>>> the Yoga 900 has an accelerometer amongst other sensors (ambient light?)
>>> exported over IIO.
>>>
>>> But, these sensors seem to not be updating at all with a 4.4-rc5+ kernel (a
>>> set of patches from https://lkml.org/lkml/2015/11/30/441 applied to Linus'
>>> tree).
>>>
>>> The odd part is at some point in messing with this, I'm fairly sure it did work!
>>> That is,
>>>
>>> `watch -n 0.1 cat '/sys/bus/iio/devices/iio:device'*/*raw*`
>>
>> Can you send us a sample of the output? Also, would be
>> good to identify the exact driver for accel.
>
> cat /sys/bus/iio/devices/iio:device*/*raw*
> 65478
> 7
> 1023
> 0
> 0
> 0
> 100
> -539062
> -742187
> 1292968
> 1592
> 64932
> 2
> 275
> 0 0 0 0
>
> Now, I should say that I distinctly remember at some point waving my
> laptop around and seeing these values change ... but now they seem to
> be "stuck". Maybe it's a hardware issue or something special that
> WIndows does to leverage the IIO sensors?
>
>> Perhaps: cat /sys/bus/iio/devices/iio:device'*/name
>
> $ cat /sys/bus/iio/devices/iio:device*/name
> accel_3d

Can you list the directory of iio:device with this name (it is:
drivers/iio/accel/hid-sensor-accel-3d.c).
This is something you will be looking at for accel debugging, but it
seems more like
standard

> gyro_3d
> als
> magn_3d
> incli_3d
> dev_rotation
>
>
>>>
>>> showed updating values as I moved the laptop around.
>>>
>>> I've not done any accelerometer debugging before, so any suggestion on
>>> where to start would be greatly appreciated!
>>
>> Did you applied some patches and recompiled the kernel? Or when it did stopped
>> working?
>
> As far as I can tell, it only worked that one one time and hasn't
> since. Although your question does make me wonder *which* kernel I was
> on that I experienced the values changing. Let me go back to a stock
> 4.4-rc5 and see.

Did you compile the stock kernel? It might be that .dts file you are
using (or defconfig)
is not correct.
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