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Paul Cercueil 9b5db7aab4 Input: goodix - poll the 'buffer status' bit before reading data
The Goodix panel triggers an interrupt on touch events. However, its
registers will contain the valid values a short time after the
interrupt, and not when it's raised. At that moment, the 'buffer status'
bit is set.

Previously, if the 'buffer status' bit was not set when the registers
were read, the data was discarded and no input event was emitted,
causing "finger down" or "finger up" events to be missed sometimes.

This went unnoticed until v4.9, as the DesignWare I2C driver commonly
used with this driver had enough latency for that bug to never trigger
until commit 2702ea7dbe ("i2c: designware: wait for disable/enable only
if necessary").

Now, in the IRQ handler we will poll (with a timeout) the 'buffer status'
bit and process the data of the panel as soon as this bit gets set.

Note that the Goodix panel will send a few spurious interrupts after the
'finger up' event, in which the 'buffer status' bit will never be set.

Cc: Bastien Nocera <hadess@hadess.net>
Cc: russianneuromancer@ya.ru
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
[hdegoede@redhat.com: Change poll loop to use jiffies,
                      add comment about typical poll time]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
[dtor: rearranged control flow a bit to avoid explicit goto and double
check]
Reviewed-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2017-10-19 16:50:39 -07:00
Documentation Input: add a driver for PWM controllable vibrators 2017-09-04 12:13:24 -07:00
arch ARM: pxa/raumfeld: mark rotary encoder properties as __initconst 2017-07-25 13:37:14 -07:00
block block: provide bio_uninit() free freeing integrity/task associations 2017-06-28 15:30:13 -06:00
certs scripts/spelling.txt: add "intialise(d)" pattern and fix typo instances 2017-05-08 17:15:13 -07:00
crypto crypto : asymmetric_keys : verify_pefile:zero memory content before freeing 2017-06-09 13:29:50 +10:00
drivers Input: goodix - poll the 'buffer status' bit before reading data 2017-10-19 16:50:39 -07:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2017-06-30 10:22:59 -07:00
include Input: uinput - avoid FF flush when destroying device 2017-09-21 16:31:22 -07:00
init Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00
ipc mm: introduce kv[mz]alloc helpers 2017-05-08 17:15:12 -07:00
kernel Two fixes: 2017-06-30 17:18:57 -07:00
lib driver core: emit uevents when device is bound to a driver 2017-07-22 11:59:23 +02:00
mm slub: make sysfs file removal asynchronous 2017-06-23 16:15:55 -07:00
net net: handle NAPI_GRO_FREE_STOLEN_HEAD case also in napi_frags_finish() 2017-06-29 15:54:13 -04:00
samples samples/bpf: run cleanup routines when receiving SIGTERM 2017-05-11 21:43:30 -04:00
scripts Kbuild fixes for v4.12 (2nd) 2017-06-24 16:18:00 -07:00
security selinux: fix double free in selinux_parse_opts_str() 2017-06-13 17:34:22 +10:00
sound ALSA: hda - Fix endless loop of codec configure 2017-06-28 12:10:05 +02:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-01 08:46:52 -07:00
usr initramfs: fix disabling of initramfs (and its compression) 2017-06-02 15:07:37 -07:00
virt KVM: arm/arm64: Handle possible NULL stage2 pud when ageing pages 2017-06-06 15:28:40 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS Merge branch 'bind_unbind' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core into next 2017-07-24 16:51:18 -07:00
Makefile Linux 4.12 2017-07-02 16:07:02 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.