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| author |   Vasily Khoruzhick <anarsoul@gmail.com> | 2020-05-02 12:31:20 -0700 |
|---|---|---|
| committer |   Takashi Iwai <tiwai@suse.de> | 2020-05-02 22:31:32 +0200 |
| commit | c55f5692748cdf7b6eee651dd91f4f3a84307e98 (patch) | |
| tree | 08fbdc833532f8dbe8ddecaa1e88be3508740de5 /sound/usb/line6 | |
| parent | ALSA: line6: hwdep: add support for O_NONBLOCK opening mode (diff) | |
| download | linux-dev-c55f5692748cdf7b6eee651dd91f4f3a84307e98.tar.xz linux-dev-c55f5692748cdf7b6eee651dd91f4f3a84307e98.zip | |
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/line6')
| -rw-r--r-- | sound/usb/line6/driver.c | 16 |
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 */ |