mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2025-01-19 14:06:29 +07:00
483180281f
If userspace requests current KEY-state, they very likely assume that no such events are pending in the output queue of the evdev device. Otherwise, they will parse events which they already handled via EVIOCGKEY(). For XKB applications this can cause irreversible keyboard states if a modifier is locked multiple times because a CTRL-DOWN event is handled once via EVIOCGKEY() and once from the queue via read(), even though it should handle it only once. Therefore, lets do the only logical thing and flush the evdev queue atomically during this ioctl. We only flush events that are affected by the given ioctl. This only affects boolean events like KEY, SND, SW and LED. ABS, REL and others are not affected as duplicate events can be handled gracefully by user-space. Note: This actually breaks semantics of the evdev ABI. However, investigations showed that userspace already expects the new semantics and we end up fixing at least all XKB applications. All applications that are aware of this race-condition mirror the KEY state for each open-file and detect/drop duplicate events. Hence, they do not care whether duplicates are posted or not and work fine with this fix. Also note that we need proper locking to guarantee atomicity and avoid dead-locks. event_lock must be locked before queue_lock (see input-core). However, we can safely release event_lock while flushing the queue. This allows the input-core to proceed with pending events and only stop if it needs our queue_lock to post new events. This should guarantee that we don't block event-dispatching for too long while flushing a single event queue. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Peter Hutterer <peter.hutterer@who-t.net> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> |
||
|---|---|---|
| .. | ||
| gameport | ||
| joystick | ||
| keyboard | ||
| misc | ||
| mouse | ||
| serio | ||
| tablet | ||
| touchscreen | ||
| apm-power.c | ||
| evbug.c | ||
| evdev.c | ||
| ff-core.c | ||
| ff-memless.c | ||
| input-compat.c | ||
| input-compat.h | ||
| input-mt.c | ||
| input-polldev.c | ||
| input.c | ||
| joydev.c | ||
| Kconfig | ||
| Makefile | ||
| matrix-keymap.c | ||
| mousedev.c | ||
| sparse-keymap.c | ||