Re: [PATCH] HID: i2c-hid: Add 60ms delay after SET_POWER ON

[Hans de Goede]

Hi,

On 8/11/20 8:00 AM, Kai-Heng Feng wrote:
> Hi Hans,
>
> > On Aug 11, 2020, at 00:13, Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> >
> > Hi,
> >
> > On 10-08-2020 16:29, Kai-Heng Feng wrote:
> > > Goodix touchpad fails to operate in I2C mode after system suspend.
> > > According to the vendor, Windows is more forgiving and there's a 60ms
> > > delay after SET_POWER ON command.
> > > So let's do the same here, to workaround for the touchpads that depend
> > > on the delay.
> > > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
> >
> > Interesting I send a very similar patch a couple of days ago,
> > after debugging some touchpads issues on a BMAX Y13 laptop:
> >
> > https://patchwork.kernel.org/patch/11701541/
> >
> > If you look at that patch you will see that if we add a
> > sleep on power-on to i2c_hid_set_power(), we can remove
> > an existing sleep after power-on from i2c_hid_hwreset().
> >
> > And there is an interesting comment there which should
> > probably be moved (as my patch does) and corrected for the
> > new knowledge so that people reading the code in the future
> > now why the sleep is there.
>
> Thanks for the info.
> Can you please update your patch with 60ms to supersede mine?

Sure, done.

Regards,

Hans


> > Other then that we've come to the same conclusion, but
> > your sleep is much longer. I guess that is ok though,
> > are you sure we need 60ms as a minimum?
> > Is that what goodix
> > said?
>
> Yes, I was told by Goodix that the 60ms delay is needed.
>
> Kai-Heng
>
> > Regards,
> >
> > Hans
> >
> >
> > > ---
> > >   drivers/hid/i2c-hid/i2c-hid-core.c | 3 +++
> > >   1 file changed, 3 insertions(+)
> > > diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
> > > index 294c84e136d7..7b24a27fad95 100644
> > > --- a/drivers/hid/i2c-hid/i2c-hid-core.c
> > > +++ b/drivers/hid/i2c-hid/i2c-hid-core.c
> > > @@ -419,6 +419,9 @@ static int i2c_hid_set_power(struct i2c_client *client, int power_state)
> > >   	if (ret)
> > >   		dev_err(&client->dev, "failed to change power setting.\n");
> > >   +	if (!ret && power_state == I2C_HID_PWR_ON)
> > > +		msleep(60);
> > > +
> > >   set_pwr_exit:
> > >   	return ret;
> > >   }