At least POD HD500 uses message-based communication, both sides can send messages. Add poll callback so application can wait for device messages without using busy loop.
Signed-off-by: Vasily Khoruzhick anarsoul@gmail.com --- sound/usb/line6/driver.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c index 86adf87d57f0..7629116f570e 100644 --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -630,11 +630,27 @@ line6_hwdep_write(struct snd_hwdep *hwdep, const char __user *data, long count, return rv; }
+static __poll_t +line6_hwdep_poll(struct snd_hwdep *hwdep, struct file *file, poll_table *wait) +{ + __poll_t rv; + struct usb_line6 *line6 = hwdep->private_data; + + poll_wait(file, &line6->messages.wait_queue, wait); + + mutex_lock(&line6->messages.read_lock); + rv = kfifo_len(&line6->messages.fifo) == 0 ? 0 : EPOLLIN | EPOLLRDNORM; + mutex_unlock(&line6->messages.read_lock); + + return rv; +} + static const struct snd_hwdep_ops hwdep_ops = { .open = line6_hwdep_open, .release = line6_hwdep_release, .read = line6_hwdep_read, .write = line6_hwdep_write, + .poll = line6_hwdep_poll, };
/* Insert into circular buffer */