ALSA: USB-audio: Break out creation of silent urbs from prepare_outbound_urb()

Refactoring in preparation for adding Zoom R16/24 quirk.
No functional change.

Signed-off-by: Ricard Wanderlof <ricardw@axis.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 27 insertions, 19 deletions

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index a77d9c812dc6..825a06ce83a9 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -183,13 +183,38 @@ static void retire_inbound_urb(struct snd_usb_endpoint *ep,
                 ep->retire_data_urb(ep->data_subs, urb);
 }
 
+static void prepare_silent_urb(struct snd_usb_endpoint *ep,
+                               struct snd_urb_ctx *ctx)
+{
+        struct urb *urb = ctx->urb;
+        unsigned int offs = 0;
+        int i;
+
+        for (i = 0; i < ctx->packets; ++i) {
+                int counts;
+
+                if (ctx->packet_size[i])
+                        counts = ctx->packet_size[i];
+                else
+                        counts = snd_usb_endpoint_next_packet_size(ep);
+
+                urb->iso_frame_desc[i].offset = offs * ep->stride;
+                urb->iso_frame_desc[i].length = counts * ep->stride;
+                offs += counts;
+        }
+
+        urb->number_of_packets = ctx->packets;
+        urb->transfer_buffer_length = offs * ep->stride;
+        memset(urb->transfer_buffer, ep->silence_value,
+               offs * ep->stride);
+}
+
 /*
  * Prepare a PLAYBACK urb for submission to the bus.
  */
 static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
                                  struct snd_urb_ctx *ctx)
 {
-        int i;
         struct urb *urb = ctx->urb;
         unsigned char *cp = urb->transfer_buffer;
 
@@ -201,24 +226,7 @@ static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
                         ep->prepare_data_urb(ep->data_subs, urb);
                 } else {
                         /* no data provider, so send silence */
-                        unsigned int offs = 0;
-                        for (i = 0; i < ctx->packets; ++i) {
-                                int counts;
-
-                                if (ctx->packet_size[i])
-                                        counts = ctx->packet_size[i];
-                                else
-                                        counts = snd_usb_endpoint_next_packet_size(ep);
-
-                                urb->iso_frame_desc[i].offset = offs * ep->stride;
-                                urb->iso_frame_desc[i].length = counts * ep->stride;
-                                offs += counts;
-                        }
-
-                        urb->number_of_packets = ctx->packets;
-                        urb->transfer_buffer_length = offs * ep->stride;
-                        memset(urb->transfer_buffer, ep->silence_value,
-                               offs * ep->stride);
+                        prepare_silent_urb(ep, ctx);
                 }
                 break;