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

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Date:	Wed, 16 Dec 2015 14:37:05 -0800
From:	Nish Aravamudan <nish.aravamudan@...il.com>
To:	Crt Mori <cmo@...exis.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.)

Hi,

On Wed, Dec 16, 2015 at 2:22 PM, Crt Mori <cmo@...exis.com> wrote:
> 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

/sys/bus/iio/devices/iio:device0/name
gyro_3d
/sys/bus/iio/devices/iio:device1/name
dev_rotation
/sys/bus/iio/devices/iio:device2/name
als
/sys/bus/iio/devices/iio:device3/name
magn_3d
/sys/bus/iio/devices/iio:device4/name
accel_3d
/sys/bus/iio/devices/iio:device5/name
incli_3d

are all the IIO sensors, sorry about that!

>> 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.

I compiled the stock kernel, based off the the Ubuntu 15.04 .config,
trimmed to account for the hardware I have on the system. I can attach
the .config if that will be useful.

I just went back to 4.4-rc4 and it also didn't seem to have any
updates to the raw file contents.

-Nish
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