diff options
| author | David Herrmann <dh.herrmann@gmail.com> | 2013-10-02 15:47:28 +0400 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2013-10-07 19:08:26 +0400 |
| commit | f50f9aabf32db7414551ffdfdccc71be5f3d6e7d (patch) | |
| tree | 1d624ee07097e1548551f77dfa537cff6400619b /drivers/hid/hid-wiimote.h | |
| parent | 7da7cbbbeb60e0939fecdf9723b388136c175e5c (diff) | |
| download | linux-f50f9aabf32db7414551ffdfdccc71be5f3d6e7d.tar.xz | |
HID: wiimote: fix FF deadlock
The input core has an internal spinlock that is acquired during event
injection via input_event() and friends but also held during FF callbacks.
That means, there is no way to share a lock between event-injection and FF
handling. Unfortunately, this is what is required for wiimote state
tracking and what we do with state.lock and input->lock.
This deadlock can be triggered when using continuous data reporting and FF
on a wiimote device at the same time. I takes me at least 30m of
stress-testing to trigger it but users reported considerably shorter
times (http://bpaste.net/show/132504/) when using some gaming-console
emulators.
The real problem is that we have two copies of internal state, one in the
wiimote objects and the other in the input device. As the input-lock is
not supposed to be accessed from outside of input-core, we have no other
chance than offloading FF handling into a worker. This actually works
pretty nice and also allows to implictly merge fast rumble changes into a
single request.
Due to the 3-layered workers (rumble+queue+l2cap) this might reduce FF
responsiveness. Initial tests were fine so lets fix the race first and if
it turns out to be too slow we can always handle FF out-of-band and skip
the queue-worker.
Cc: <stable@vger.kernel.org> # 3.11+
Reported-by: Thomas Schneider
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/hid/hid-wiimote.h')
| -rw-r--r-- | drivers/hid/hid-wiimote.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/hid/hid-wiimote.h b/drivers/hid/hid-wiimote.h index f1474f372c0b..75db0c400037 100644 --- a/drivers/hid/hid-wiimote.h +++ b/drivers/hid/hid-wiimote.h @@ -133,13 +133,15 @@ struct wiimote_state { __u8 *cmd_read_buf; __u8 cmd_read_size; - /* calibration data */ + /* calibration/cache data */ __u16 calib_bboard[4][3]; + __u8 cache_rumble; }; struct wiimote_data { struct hid_device *hdev; struct input_dev *input; + struct work_struct rumble_worker; struct led_classdev *leds[4]; struct input_dev *accel; struct input_dev *ir; |