linux/drivers/input
Benjamin Tissoires c627589282 Input - mt: Fix input_mt_get_slot_by_key
The case occurred recently with a touchscreen using twice a slot during a
single EV_SYN event:

E: 0.288415 0000 0000 0000      # ------------ SYN_REPORT (0) ----------
E: 0.296207 0003 002f 0000      # EV_ABS / ABS_MT_SLOT          0
E: 0.296207 0003 0039 -001      # EV_ABS / ABS_MT_TRACKING_ID   -1
E: 0.296207 0003 002f 0001      # EV_ABS / ABS_MT_SLOT          1
E: 0.296207 0003 0035 0908      # EV_ABS / ABS_MT_POSITION_X    908
E: 0.296207 0003 0036 1062      # EV_ABS / ABS_MT_POSITION_Y    1062
E: 0.296207 0003 002f 0000      # EV_ABS / ABS_MT_SLOT          0
E: 0.296207 0003 0039 8787      # EV_ABS / ABS_MT_TRACKING_ID   8787
E: 0.296207 0003 0035 1566      # EV_ABS / ABS_MT_POSITION_X    1566
E: 0.296207 0003 0036 0861      # EV_ABS / ABS_MT_POSITION_Y    861
E: 0.296207 0003 0000 0908      # EV_ABS / ABS_X                908
E: 0.296207 0003 0001 1062      # EV_ABS / ABS_Y                1062
E: 0.296207 0000 0000 0000      # ------------ SYN_REPORT (0) ----------

This occurred because while having already slots 0 and 1 assigned, the
touchscreen sent:

0.293377 Tip Switch: 0 | Contact Id: 0 | X:  539 | Y: 1960 | Contact Count: 3
0.294783 Tip Switch: 1 | Contact Id: 1 | X:  908 | Y: 1062 | Contact Count: 0
0.296187 Tip Switch: 1 | Contact Id: 2 | X: 1566 | Y:  861 | Contact Count: 0

Slot 0 is released correclty, but when we look for Contact ID 2, the slot
0 is then picked up again because it is marked as inactive (trackingID < 0).

This is wrong, and we should not reuse a slot in the same frame.
The test should also check for input_mt_is_used().

In addition, we need to initialize mt->frame to an other value than 0.
With mt->frame being 0, all slots are tags as currently used, and so
input_mt_get_slot_by_key() would return -1 for all requests.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=88903

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2015-04-07 15:16:36 +02:00
..
gameport Input: initialize device counter variables with -1 2014-12-03 15:27:17 -08:00
joystick Merge branch 'next' into for-linus 2014-12-15 20:32:42 -08:00
keyboard Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2014-12-30 16:59:59 -08:00
misc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2014-12-17 10:06:02 -08:00
mouse Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2015-02-01 13:16:40 -08:00
serio Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2015-02-01 13:16:40 -08:00
tablet Merge branch 'wacom' into next 2014-08-06 23:31:48 -07:00
touchscreen Revert "Input: atmel_mxt_ts - use deep sleep mode when stopped" 2014-12-31 12:59:34 -08:00
apm-power.c Input: random formatting fixes 2012-08-21 22:29:49 -07:00
evbug.c
evdev.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2014-12-30 16:59:59 -08:00
ff-core.c Input: random formatting fixes 2012-08-21 22:29:49 -07:00
ff-memless.c Input: random formatting fixes 2012-08-21 22:29:49 -07:00
input-compat.c compat: Use COMPAT_USE_64BIT_TIME in the input subsystem 2012-02-20 12:48:47 -08:00
input-compat.h compat: Use COMPAT_USE_64BIT_TIME in the input subsystem 2012-02-20 12:48:47 -08:00
input-mt.c Input - mt: Fix input_mt_get_slot_by_key 2015-04-07 15:16:36 +02:00
input-polldev.c Input: implement managed polled input devices 2014-05-14 16:40:04 -07:00
input.c Input: optimize events_per_packet count calculation 2014-12-15 21:45:55 -08:00
joydev.c Input: fix use-after-free introduced with dynamic minor changes 2012-10-22 08:50:37 +03:00
Kconfig Input: mousedev - allow disabling even without CONFIG_EXPERT 2013-10-31 08:46:07 -07:00
Makefile Input: matrix-keymap - uninline and prepare for device tree support 2012-05-10 22:38:47 -07:00
matrix-keymap.c input: Export matrix_keypad_parse_of_params() 2013-04-19 00:31:13 +02:00
mousedev.c Input: mousedev - fix race when creating mixed device 2014-03-29 14:44:23 -07:00
sparse-keymap.c treewide: Fix typo in Documentation/DocBook 2014-02-19 14:58:17 +01:00