Messages in this thread | | | From | Benjamin Tissoires <> | Date | Mon, 1 Oct 2018 09:00:52 +0200 | Subject | Re: [PATCH] HID: i2c-hid: Add a small delay after powering on/off the device |
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On Mon, Oct 1, 2018 at 5:53 AM Kai-Heng Feng <kai.heng.feng@canonical.com> wrote: > > Raydium touchpanel (2386:4B33) sometimes does not workin desktop session > although it works in display manager. > > During user logging, the display manager exits, close the HID device, > then the device gets runtime suspended and powered off. The desktop > session begins shortly after, opens the HID device, then the device gets > runtime resumed and powered on. > > If the trasition from display manager to desktop sesesion is fast, the > touchpanel cannot switch from powered off to powered on in short > timeframe. So add a small delay to workaround the issue.
I think you want something similar to https://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid.git/commit/?h=for-next&id=807588ac92018bde88a1958f546438e840eb0158
> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> > --- > drivers/hid/i2c-hid/i2c-hid.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c > index f3076659361a..ff5682cc1bce 100644 > --- a/drivers/hid/i2c-hid/i2c-hid.c > +++ b/drivers/hid/i2c-hid/i2c-hid.c > @@ -409,6 +409,8 @@ 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"); > + else > + msleep(20);
We shouldn't have this error in the first place, so adding a timeout will just add a band-aid on top of an other issue.
I really think the solution from Anisse would work in your case and will be nicer.
Cheers, Benjamin
> > set_pwr_exit: > return ret; > -- > 2.17.1 >
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