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

[Hans de Goede <hdegoede@redhat.com>]

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@redhat.com> 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@canonical.com>
>>
>> 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;
>>>   }
>>
>