-----Original Message-----
From: linux-input-owner@vger.kernel.org [mailto:linux-input-owner@vger.kernel.org] On Behalf Of Brad Baker
Sent: 11 September, 2016 0:21
To: bastien nocera
Cc: linux-input@vger.kernel.org
Subject: Goodix touchscreen works intermittently, fails reading config info.

Summary: Goodix touchscreen works intermittently, fails reading config info.
 https://bugzilla.kernel.org/show_bug.cgi?id=156511

Description:  Chuwi Hi12 tablet with Intel cherry-trail Atom Z8300,
the touchscreen does work after bootup most of the time, but sometimes
it does not work without running modprobe.  When it fails the dmesg
log shows the error "Invalid config, using defaults" and when it works
this error is not present.

Module: goodix, goodix_backport
Linux version 4.8.0-040800rc5-generic (kernel@tangerine) (gcc version
6.2.0 20160830 (Ubuntu 6.2.0-2ubuntu11) ) #201609041832 SMP Sun Sep 4
22:34:01 UTC 2016

dmesg log when it's failing:
[ 10.012314] Goodix-TS i2c-GDIX1001:00: ID 9111, version: 1060
[ 10.017711] Goodix-TS i2c-GDIX1001:00: Invalid config, using defaults
[ 10.018021] input: Goodix Capacitive TouchScreen as
/devices/pci0000:00/808622C1:05/i2c-13/i2c-GDIX1001:00/input/input6

details given in bugzilla #156511

Hi Brad,

I had similar problems with some Goodix devices until I enabled the
reset sequence [1].

Although the touch screen was initialized and I could read/write to/from
the device, I read only 0s from the configuration registers. The datasheet
recommends using the reset procedure at power on, so I could not find any
information on how to make the device work reliably without it. Resetting the
device at boot fixed the problem for me. For backwards compatibility, the
reset sequence is only available if the interrupt and reset gpio pins are
connected and configured through _DSD properties in the ACPI table or DT
properties.

One reason for the touchscreen not working in this case is that the interrupts
are not properly configured. I noticed in the Bugzilla details that you already
tried changing the default value for trigger_type to the one read from the device.
Did that work?

Regards,
Irina

[1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ec6e1b4082d9f5b0858ce33169a1c22a27a982f6