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authorDavid Herrmann <dh.herrmann@gmail.com>2013-05-05 23:12:50 +0200
committerJiri Kosina <jkosina@suse.cz>2013-06-03 11:07:00 +0200
commitd758b1f0c527aedc5e83a565a0737d9ac21ea46a (patch)
tree20707221091b2e594df2e18a164d94ccf2e05490
parent6b80bb94dc61a7f702df13c6c7e8edee331d0a9a (diff)
HID: wiimote: wake up if output queue failed
Our output queue is asynchronous but synchronous reports may wait for a response to their request. Therefore, wake them up unconditionally if an output report couldn't be sent. But keep the report ID intact so we don't incorrectly assume our request succeeded. Note that the underlying connection is required to be reliable and does retransmission itself. So it is safe to assume that if the transmission fails, the device is in inconsistent state. Hence, we abort every request if any output report fails. No need to verify which report failed. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
-rw-r--r--drivers/hid/hid-wiimote-core.c24
-rw-r--r--drivers/hid/hid-wiimote.h19
2 files changed, 38 insertions, 5 deletions
diff --git a/drivers/hid/hid-wiimote-core.c b/drivers/hid/hid-wiimote-core.c
index 00a9b6fa518..a025d2104d3 100644
--- a/drivers/hid/hid-wiimote-core.c
+++ b/drivers/hid/hid-wiimote-core.c
@@ -58,11 +58,11 @@ static enum power_supply_property wiimote_battery_props[] = {
/* output queue handling */
-static ssize_t wiimote_hid_send(struct hid_device *hdev, __u8 *buffer,
- size_t count)
+static int wiimote_hid_send(struct hid_device *hdev, __u8 *buffer,
+ size_t count)
{
__u8 *buf;
- ssize_t ret;
+ int ret;
if (!hdev->hid_output_raw_report)
return -ENODEV;
@@ -84,14 +84,20 @@ static void wiimote_queue_worker(struct work_struct *work)
struct wiimote_data *wdata = container_of(queue, struct wiimote_data,
queue);
unsigned long flags;
+ int ret;
spin_lock_irqsave(&wdata->queue.lock, flags);
while (wdata->queue.head != wdata->queue.tail) {
spin_unlock_irqrestore(&wdata->queue.lock, flags);
- wiimote_hid_send(wdata->hdev,
+ ret = wiimote_hid_send(wdata->hdev,
wdata->queue.outq[wdata->queue.tail].data,
wdata->queue.outq[wdata->queue.tail].size);
+ if (ret < 0) {
+ spin_lock_irqsave(&wdata->state.lock, flags);
+ wiimote_cmd_abort(wdata);
+ spin_unlock_irqrestore(&wdata->state.lock, flags);
+ }
spin_lock_irqsave(&wdata->queue.lock, flags);
wdata->queue.tail = (wdata->queue.tail + 1) % WIIMOTE_BUFSIZE;
@@ -108,7 +114,9 @@ static void wiimote_queue(struct wiimote_data *wdata, const __u8 *buffer,
if (count > HID_MAX_BUFFER_SIZE) {
hid_warn(wdata->hdev, "Sending too large output report\n");
- return;
+
+ spin_lock_irqsave(&wdata->queue.lock, flags);
+ goto out_error;
}
/*
@@ -134,8 +142,14 @@ static void wiimote_queue(struct wiimote_data *wdata, const __u8 *buffer,
wdata->queue.head = newhead;
} else {
hid_warn(wdata->hdev, "Output queue is full");
+ goto out_error;
}
+ goto out_unlock;
+
+out_error:
+ wiimote_cmd_abort(wdata);
+out_unlock:
spin_unlock_irqrestore(&wdata->queue.lock, flags);
}
diff --git a/drivers/hid/hid-wiimote.h b/drivers/hid/hid-wiimote.h
index 301607da771..34417021606 100644
--- a/drivers/hid/hid-wiimote.h
+++ b/drivers/hid/hid-wiimote.h
@@ -195,6 +195,16 @@ static inline void wiimote_cmd_complete(struct wiimote_data *wdata)
complete(&wdata->state.ready);
}
+/* requires the state.lock spinlock to be held */
+static inline void wiimote_cmd_abort(struct wiimote_data *wdata)
+{
+ /* Abort synchronous request by waking up the sleeping caller. But
+ * reset the state.cmd field to an invalid value so no further event
+ * handlers will work with it. */
+ wdata->state.cmd = WIIPROTO_REQ_MAX;
+ complete(&wdata->state.ready);
+}
+
static inline int wiimote_cmd_acquire(struct wiimote_data *wdata)
{
return mutex_lock_interruptible(&wdata->state.sync) ? -ERESTARTSYS : 0;
@@ -223,11 +233,17 @@ static inline int wiimote_cmd_wait(struct wiimote_data *wdata)
{
int ret;
+ /* The completion acts as implicit memory barrier so we can safely
+ * assume that state.cmd is set on success/failure and isn't accessed
+ * by any other thread, anymore. */
+
ret = wait_for_completion_interruptible_timeout(&wdata->state.ready, HZ);
if (ret < 0)
return -ERESTARTSYS;
else if (ret == 0)
return -EIO;
+ else if (wdata->state.cmd != WIIPROTO_REQ_NULL)
+ return -EIO;
else
return 0;
}
@@ -236,9 +252,12 @@ static inline int wiimote_cmd_wait_noint(struct wiimote_data *wdata)
{
unsigned long ret;
+ /* no locking needed; see wiimote_cmd_wait() */
ret = wait_for_completion_timeout(&wdata->state.ready, HZ);
if (!ret)
return -EIO;
+ else if (wdata->state.cmd != WIIPROTO_REQ_NULL)
+ return -EIO;
else
return 0;
}