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>

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index a77d9c812dc6def5c4f4a2389fd959134febcde3..825a06ce83a9c2fa696fbdb7c0a86000dd9ce8c4 100644 (file)
--- 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;