Messages in this thread | | | Subject | Re: [PATCH] HID: i2c-hid: Add a small delay after powering on/off the device | From | Kai Heng Feng <> | Date | Mon, 1 Oct 2018 15:13:35 +0800 |
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> On Oct 1, 2018, at 3:00 PM, Benjamin Tissoires > <benjamin.tissoires@redhat.com> wrote: > > 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.
The Hantick one requires 2.5 seconds delay, the Raydium one requires much less. Also it doesn't have the input shift issue.
So disabling runtime PM entirely is a little overkill in this case.
Maybe there's a better approach?
Kai-Heng
> > Cheers, > Benjamin > >> set_pwr_exit: >> return ret; >> -- >> 2.17.1
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