linux-kernel - Re: [PATCH] HID: i2c-hid: Disable runtime PM on Goodix touchpad

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Message-Id: <663EE74C-02E8-49DB-A197-2022AFE2D863@canonical.com>
Date:   Wed, 16 Jan 2019 16:21:21 +0800
From:   Kai Heng Feng <kai.heng.feng@...onical.com>
To:     Jiri Kosina <jikos@...nel.org>
Cc:     benjamin.tissoires@...hat.com, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] HID: i2c-hid: Disable runtime PM on Goodix touchpad



> On Jan 14, 2019, at 19:18, Jiri Kosina <jikos@...nel.org> wrote:
> 
> On Mon, 14 Jan 2019, Kai-Heng Feng wrote:
> 
>> A Goodix touchpad doesn't work. Touching the touchpad can trigger IRQ
>> but there's no input event from HID subsystem.
>> 
>> Turns out it reports some invalid data:
>> [   22.136630] i2c_hid i2c-DELL091F:00: input: 0b 00 01 00 00 00 00 00 00 00 00
>> 
>> After some trial and error, it's another device that doesn't work well
>> with ON/SLEEP commands. Disable runtime PM to fix the issue.
> 
> Thanks, I've now applied the patch to for-5.0/upstream-fixes. I am 
> wondering though we are we seeing these at all - do other OSes not do the 
> runtime PM on i2c at all?

According to the vendor, Windows does use ON/SLEEP, but infrequently.

We can use pm_runtime_use_autosuspend() to reduce the frequency of
ON/SLEEP commands, but it’s just papering over the touchpad firmware
bug.

Kai-Heng

> 
> -- 
> Jiri Kosina
> SUSE Labs
>