Making sense of i2c

Colin McKinnon colin.mckinnon at
Mon Jan 16 19:28:33 UTC 2017

Thanks Kenny, Ray,

Lenovo seem to use very differently sourced parts for similarly named
devices (and the touchscreen usually hangs off the GPU - which is *very*
different on Intel vs AMD).

>From what I see the there have been a lot of changes in the i2c code since
3.15. That it is supported by the generic driver in MSWindows makes me
think its not particularly esoteric hardware I'm dealing with - and likely
caused by the timeout scanning the bus at startup. It's a recent kernel on
the laptop (not sitting in front of it right now) so I was planning on
trying a different distro - but was going to try an older one first.

As to whether touch works with Wayland....I've yet to find out :) but
otherwise I was rather impressed comparing the 2 on the laptop. Everything
was a lot smoother with Wayland - and no stability/compatability issues -
not that I've seen any with Xorg recently, but it has been around a lot

I'll let you know how I get on with the touchscreen.


On 16 January 2017 at 09:57, Kenny Duffus via Scottish <
scottish at> wrote:

> On Sunday, 15 January 2017 11:58:38 GMT, Colin McKinnon via Scottish wrote:
>> Hi all,
>> I bought my daughter a Lenovo Yoga 510-14AST for Christmas. Everything
>> works in Linux (Fedora 25) except for the touchscreen.
>> Its not appearing as a USB device. At startup there is an error as it
>> scans
>> the i2c bus (which seems a likely place to find the device).
>> Its currently running dual-boot with MSWindows. There I can see that the
>> synaptic.sys driver is loaded, but I don't know how to divine any further
>> details on how it is plumbed.
> Hi
> Not too sure what the difference is but with KDE Neon (based on ubuntu
> xenial base) touch screen worked out the box on the 510-14ISK (not sure how
> much difference there is between the models)
> In lsusb and lspci there is no mention of touch however in hwinfo I get:
>  hid-multitouch: /devices/pci0000:00/0000:00:15
> .1/i2c_designware.1/i2c-14/i2c-SYNA7501:00/0018:06CB:16C9.0002
>  hid-multitouch: module = hid_multitouch
>    input device: bus = hid, bus_id = 0018:06CB:16C9.0002 driver =
> hid-multitouch
>    input device: bus = hid, bus_id = 0018:06CB:16C9.0002 driver =
> hid-multitouch
>  E: DRIVER=hid-multitouch
>  <6>[    3.793244] hid-multitouch 0018:06CB:16C9.0002: input,hidraw0: I2C
> HID v1.00 Device [SYNA7501:00 06CB:16C9] on i2c-SYNA7501:00
>  hid_multitouch 20480 0 - Live 0x0000000000000000
>  hid 118784 3 hid_sensor_hub,hid_multitouch,i2c_hid, Live
> 0x0000000000000000
> Maybe it might be worth poking it with a *ubuntu based distro to help you
> narrow down what the differences are
> --
>         Kenny

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