ALSA: usb-audio: add a workaround for the NuForce UDH-100

[linux-imx.git] / sound / usb / card.c

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 803953a9bff338056795c888cecc9d7fb9c6daa2..2da8ad75fd96c7c0245dfca05c9997e5c3d355a1 100644 (file)
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -243,6 +243,21 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
                struct usb_interface_assoc_descriptor *assoc =
                        usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
 
+               if (!assoc) {
+                       /*
+                        * Firmware writers cannot count to three.  So to find
+                        * the IAD on the NuForce UDH-100, also check the next
+                        * interface.
+                        */
+                       struct usb_interface *iface =
+                               usb_ifnum_to_if(dev, ctrlif + 1);
+                       if (iface &&
+                           iface->intf_assoc &&
+                           iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
+                           iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
+                               assoc = iface->intf_assoc;
+               }
+
                if (!assoc) {
                        snd_printk(KERN_ERR "Audio class v2 interfaces need an interface association\n");
                        return -EINVAL;