when usb audio device removes, it doesn't notify the ALSA read /
write thread. due to no data transmitting any more, those threads
wait for a long timeout(10s), then detects IO error. it causes
long time blocking in upper layer read/write.
to fix this issue, wake up potential sleep thread if necessary
when audio unbind. substream & pcm may still be used after audio
unbind, and we should only set null to it in audio_pcm_close.
Signed-off-by: Qiao Zhou <zhouqiao@xxxxxxxxxxx>
---
drivers/usb/gadget/f_audio_source.c | 12 ++++++++++--
1 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/gadget/f_audio_source.c b/drivers/usb/gadget/f_audio_source.c
index c757409..2909427 100644
--- a/drivers/usb/gadget/f_audio_source.c
+++ b/drivers/usb/gadget/f_audio_source.c
@@ -620,15 +620,22 @@ static void
audio_unbind(struct usb_configuration *c, struct usb_function *f)
{
struct audio_dev *audio = func_to_audio(f);
+ struct snd_pcm_substream *substream = audio->substream;
struct usb_request *req;
while ((req = audio_req_get(audio)))
audio_request_free(req, audio->in_ep);
+ /*
+ * wake up potential sleep thread if necessary, and to timely
+ * notify ALSA write thread so that it doesn't need to wait for
+ * the 10s timeout.
+ */
+ if (substream && substream->runtime && substream->runtime->twake)
+ wake_up(&substream->runtime->tsleep);
+
snd_card_free_when_closed(audio->card);
audio->card = NULL;
- audio->pcm = NULL;
- audio->substream = NULL;
audio->in_ep = NULL;
}
@@ -670,6 +677,7 @@ static int audio_pcm_close(struct snd_pcm_substream *substream)
unsigned long flags;
spin_lock_irqsave(&audio->lock, flags);
+ audio->pcm = NULL;
audio->substream = NULL;
spin_unlock_irqrestore(&audio->lock, flags);
--
1.7.0.4
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