Hi Hans, > On Aug 11, 2020, at 00:13, Hans de Goede <hdego...@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.f...@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? > > 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; >> } >
