1 files changed, 31 insertions, 6 deletions

diff --git a/sound/usb/caiaq/audio.c b/sound/usb/caiaq/audio.c
index d0d493ca28ae..2cf87f5afed4 100644
--- a/sound/usb/caiaq/audio.c
+++ b/sound/usb/caiaq/audio.c
@@ -139,8 +139,12 @@ static void stream_stop(struct snd_usb_caiaqdev *dev)
 
         for (i = 0; i < N_URBS; i++) {
                 usb_kill_urb(dev->data_urbs_in[i]);
-                usb_kill_urb(dev->data_urbs_out[i]);
+
+                if (test_bit(i, &dev->outurb_active_mask))
+                        usb_kill_urb(dev->data_urbs_out[i]);
         }
+
+        dev->outurb_active_mask = 0;
 }
 
 static int snd_usb_caiaq_substream_open(struct snd_pcm_substream *substream)
@@ -612,8 +616,9 @@ static void read_completed(struct urb *urb)
 {
         struct snd_usb_caiaq_cb_info *info = urb->context;
         struct snd_usb_caiaqdev *dev;
-        struct urb *out;
-        int frame, len, send_it = 0, outframe = 0;
+        struct urb *out = NULL;
+        int i, frame, len, send_it = 0, outframe = 0;
+        size_t offset = 0;
 
         if (urb->status || !info)
                 return;
@@ -623,7 +628,17 @@ static void read_completed(struct urb *urb)
         if (!dev->streaming)
                 return;
 
-        out = dev->data_urbs_out[info->index];
+        /* find an unused output urb that is unused */
+        for (i = 0; i < N_URBS; i++)
+                if (test_and_set_bit(i, &dev->outurb_active_mask) == 0) {
+                        out = dev->data_urbs_out[i];
+                        break;
+                }
+
+        if (!out) {
+                log("Unable to find an output urb to use\n");
+                goto requeue;
+        }
 
         /* read the recently received packet and send back one which has
          * the same layout */
@@ -634,7 +649,8 @@ static void read_completed(struct urb *urb)
                 len = urb->iso_frame_desc[outframe].actual_length;
                 out->iso_frame_desc[outframe].length = len;
                 out->iso_frame_desc[outframe].actual_length = 0;
-                out->iso_frame_desc[outframe].offset = BYTES_PER_FRAME * frame;
+                out->iso_frame_desc[outframe].offset = offset;
+                offset += len;
 
                 if (len > 0) {
                         spin_lock(&dev->spinlock);
@@ -650,11 +666,15 @@ static void read_completed(struct urb *urb)
         }
 
         if (send_it) {
-                out->number_of_packets = FRAMES_PER_URB;
+                out->number_of_packets = outframe;
                 out->transfer_flags = URB_ISO_ASAP;
                 usb_submit_urb(out, GFP_ATOMIC);
+        } else {
+                struct snd_usb_caiaq_cb_info *oinfo = out->context;
+                clear_bit(oinfo->index, &dev->outurb_active_mask);
         }
 
+requeue:
         /* re-submit inbound urb */
         for (frame = 0; frame < FRAMES_PER_URB; frame++) {
                 urb->iso_frame_desc[frame].offset = BYTES_PER_FRAME * frame;
@@ -676,6 +696,8 @@ static void write_completed(struct urb *urb)
                 dev->output_running = 1;
                 wake_up(&dev->prepare_wait_queue);
         }
+
+        clear_bit(info->index, &dev->outurb_active_mask);
 }
 
 static struct urb **alloc_urbs(struct snd_usb_caiaqdev *dev, int dir, int *ret)
@@ -827,6 +849,9 @@ int snd_usb_caiaq_audio_init(struct snd_usb_caiaqdev *dev)
         if (!dev->data_cb_info)
                 return -ENOMEM;
 
+        dev->outurb_active_mask = 0;
+        BUILD_BUG_ON(N_URBS > (sizeof(dev->outurb_active_mask) * 8));
+
         for (i = 0; i < N_URBS; i++) {
                 dev->data_cb_info[i].dev = dev;
                 dev->data_cb_info[i].index = i;