HID: fix a lockup regression when using force feedback on a PID device
Commit 8006479c9b75fb6594a7b746af3d7f1fbb68f18f introduced a spinlock in
input_dev->event_lock, which is locked when handling input events.
However, the hid-pidff driver sleeps when handling events as it waits for
reports being sent to the device before changing the report contents
again.
This causes a system lockup when trying to use force feedback with a PID
device, a regression introduced in 2.6.24 and 2.6.23.15.
Fix it by extracting the raw report data from struct hid_report
immediately when hid_submit_report() is called, therefore allowing
drivers to change the contents of struct hid_report immediately without
affecting the already-queued transfer.
In hid-pidff, re-add the removed usbhid_wait_io() to
pidff_erase_effect() instead, to prevent a full report queue from causing
the submission to fail, thus not freeing up device memory.
pidff_erase_effect() is not called while dev->event_lock is held.
Signed-off-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
index 0113261..484e3ee 100644
--- a/drivers/hid/usbhid/hid-pidff.c
+++ b/drivers/hid/usbhid/hid-pidff.c
@@ -397,7 +397,6 @@
effect->u.condition[i].left_saturation);
pidff_set(&pidff->set_condition[PID_DEAD_BAND],
effect->u.condition[i].deadband);
- usbhid_wait_io(pidff->hid);
usbhid_submit_report(pidff->hid, pidff->reports[PID_SET_CONDITION],
USB_DIR_OUT);
}
@@ -512,7 +511,6 @@
pidff->effect_operation[PID_LOOP_COUNT].value[0] = n;
}
- usbhid_wait_io(pidff->hid);
usbhid_submit_report(pidff->hid, pidff->reports[PID_EFFECT_OPERATION],
USB_DIR_OUT);
}
@@ -548,6 +546,9 @@
int pid_id = pidff->pid_id[effect_id];
debug("starting to erase %d/%d", effect_id, pidff->pid_id[effect_id]);
+ /* Wait for the queue to clear. We do not want a full fifo to
+ prevent the effect removal. */
+ usbhid_wait_io(pidff->hid);
pidff_playback_pid(pidff, pid_id, 0);
pidff_erase_pid(pidff, pid_id);