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@xxxxxxxxx>
---
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 */
--
2.26.2
