[PATCH] ALSA: usb-audio: Don't try to submit URBs after disconnection

[Takashi Iwai <tiwai@xxxxxxx>]

USB-audio driver can still submit URBs while the device is being
disconnected, and it may result in spurious error messages like:
  usb 1-2: cannot submit urb (err = -19)
  usb 1-2: Unable to submit urb #0: -19 at snd_usb_queue_pending_output_urbs
  usb 1-2: cannot submit urb 0, error -19: no device
Although those are harmless, they are just ugly.

This patch tries to avoid spewing such error messages when the device
is already at the disconnected state.  It also skips the superfluous
xfer notification, too.

Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
 sound/usb/endpoint.c | 40 +++++++++++++++++++++++++++-------------
 1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index a385e85c4650..8f65349a06d3 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -505,13 +505,18 @@ int snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
 			return -EPIPE;
 		}
 
-		err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
+		if (!atomic_read(&ep->chip->shutdown))
+			err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
+		else
+			err = -ENODEV;
 		if (err < 0) {
-			usb_audio_err(ep->chip,
-				      "Unable to submit urb #%d: %d at %s\n",
-				      ctx->index, err, __func__);
-			if (!in_stream_lock)
-				notify_xrun(ep);
+			if (!atomic_read(&ep->chip->shutdown)) {
+				usb_audio_err(ep->chip,
+					      "Unable to submit urb #%d: %d at %s\n",
+					      ctx->index, err, __func__);
+				if (!in_stream_lock)
+					notify_xrun(ep);
+			}
 			return -EPIPE;
 		}
 
@@ -575,12 +580,17 @@ static void snd_complete_urb(struct urb *urb)
 		prepare_inbound_urb(ep, ctx);
 	}
 
-	err = usb_submit_urb(urb, GFP_ATOMIC);
+	if (!atomic_read(&ep->chip->shutdown))
+		err = usb_submit_urb(urb, GFP_ATOMIC);
+	else
+		err = -ENODEV;
 	if (err == 0)
 		return;
 
-	usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
-	notify_xrun(ep);
+	if (!atomic_read(&ep->chip->shutdown)) {
+		usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
+		notify_xrun(ep);
+	}
 
 exit_clear:
 	clear_bit(ctx->index, &ep->active_mask);
@@ -1603,11 +1613,15 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
 			goto __error;
 		}
 
-		err = usb_submit_urb(urb, GFP_ATOMIC);
+		if (!atomic_read(&ep->chip->shutdown))
+			err = usb_submit_urb(urb, GFP_ATOMIC);
+		else
+			err = -ENODEV;
 		if (err < 0) {
-			usb_audio_err(ep->chip,
-				"cannot submit urb %d, error %d: %s\n",
-				i, err, usb_error_string(err));
+			if (!atomic_read(&ep->chip->shutdown))
+				usb_audio_err(ep->chip,
+					      "cannot submit urb %d, error %d: %s\n",
+					      i, err, usb_error_string(err));
 			goto __error;
 		}
 		set_bit(i, &ep->active_mask);
-- 
2.35.3