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

Kleber Souza kleber.souza at
Wed Dec 19 08:17:43 UTC 2018

On 12/19/18 8:05 AM, Kai Heng Feng wrote:
>> 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.
> Kai-Heng

Hi Kai-Heng,

So we definitely need that first patch in full version. It would be good
to have a reference to LP: #1728244 in that patch so we can track its fix.

Could you please send it in a separate SRU request? Then we can hold
this patch series for a bit, ignoring patch 1/2 for bionic, and when
both are reviewed we apply them in the right order.



>> Thanks,
>> Kleber

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