APPLIED[Unstable] / Cmt: [SRU] [B/C/D/Unstable] [PATCH 0/2] Fix and issue that LG I2C touchscreen stops working after reboot

Kai Heng Feng kai.heng.feng at
Wed Dec 19 07:05:24 UTC 2018

> On Dec 19, 2018, at 00:33, Kleber Souza <kleber.souza at> wrote:
> On 11/29/18 6:14 AM, Kai Heng Feng wrote:
>>> On Nov 28, 2018, at 12:36 AM, Seth Forshee <seth.forshee at> wrote:
>>> On Tue, Nov 27, 2018 at 06:59:06AM +0000, Kai-Heng Feng wrote:
>>>> BugLink:
>>>> [Impact]
>>>> LG I2C touchscreen stops working after reboot.
>>>> [Fix]
>>>> Disable runtime PM for the touchscreen, which doesn't work well with
>>>> consecutive ON/SLEEP commands.
>>>> [Test]
>>>> The touchscreen works well after reboot, when runtime PM is disabled.
>>>> [Regression Potential]
>>>> None. This is a new device and the fix is limited to this particular
>>>> device.
>>> The patch did not apply to unstable, so I cherry picked the fix
>>> directly.
>> Thanks!
>>> Wrt bionic though, there's the extra prerequisite patch that looks to be
>>> affecting a different touchscreen. If so you can't really say that the
>>> regression potential is limited to a single device. You should either
>>> explain why we should also change runtime PM for that device and
>>> describe what regression testing was done, or else omit the changes for
>>> that device.
>> I missed that one, sorry. It does introduce a fix for another device.
>> The change to runtime PM is to let the driver never tries to runtime
>> suspend the device, avoiding sending too many ON/SLEEP command to
>> the device.
>> Kai-Heng
> Hi Kai-Heng,
> Was any regression test done with the hantick device affected by the
> first patch for Bionic?

No not really, since we don’t have that particular device.

That commit is a fix for LP: #1728244 but I haven’t sent an SRU for that bug.
I can split the SRU into two if you think it’s better.


> Thanks,
> Kleber

More information about the kernel-team mailing list