Currently line6 hwdep interface ignores O_NONBLOCK flag when opening device and it renders it somewhat useless when using poll.
Check for O_NONBLOCK flag when opening device and don't block read() if it is set.
Signed-off-by: Vasily Khoruzhick anarsoul@gmail.com --- sound/usb/line6/driver.c | 4 ++++ sound/usb/line6/driver.h | 1 + 2 files changed, 5 insertions(+)
diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c index 4f096685ed65..86adf87d57f0 100644 --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -550,6 +550,7 @@ static int line6_hwdep_open(struct snd_hwdep *hw, struct file *file) /* NOTE: hwdep layer provides atomicity here */
line6->messages.active = 1; + line6->messages.nonblock = file->f_flags & O_NONBLOCK ? 1 : 0;
return 0; } @@ -579,6 +580,9 @@ line6_hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count, while (kfifo_len(&line6->messages.fifo) == 0) { mutex_unlock(&line6->messages.read_lock);
+ if (line6->messages.nonblock) + return -EAGAIN; + rv = wait_event_interruptible( line6->messages.wait_queue, kfifo_len(&line6->messages.fifo) != 0); diff --git a/sound/usb/line6/driver.h b/sound/usb/line6/driver.h index e5e572ed5f30..1a4e3700c80c 100644 --- a/sound/usb/line6/driver.h +++ b/sound/usb/line6/driver.h @@ -163,6 +163,7 @@ struct usb_line6 { struct mutex read_lock; wait_queue_head_t wait_queue; unsigned int active:1; + unsigned int nonblock:1; STRUCT_KFIFO_REC_2(LINE6_BUFSIZE_LISTEN * LINE6_RAW_MESSAGES_MAXCOUNT) fifo; } messages;