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authorVasily Khoruzhick <anarsoul@gmail.com>2020-05-02 12:31:20 -0700
committerTakashi Iwai <tiwai@suse.de>2020-05-02 22:31:32 +0200
commitc55f5692748cdf7b6eee651dd91f4f3a84307e98 (patch)
tree08fbdc833532f8dbe8ddecaa1e88be3508740de5 /sound/usb
parent5c2d0de544c39407bf286d33bdcc1fb06a892d8b (diff)
downloadlinux-c55f5692748cdf7b6eee651dd91f4f3a84307e98.tar.bz2
ALSA: line6: Add poll callback for hwdep
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> Link: https://lore.kernel.org/r/20200502193120.79115-3-anarsoul@gmail.com Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb')
-rw-r--r--sound/usb/line6/driver.c16
1 files changed, 16 insertions, 0 deletions
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 */