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authorClemens Ladisch <clemens@ladisch.de>2013-03-11 20:15:34 +0100
committerTakashi Iwai <tiwai@suse.de>2013-03-12 08:35:30 +0100
commit281a6ac0f54052c81bbee156914459ba5a08f924 (patch)
treef7ad83926271528979e781fc02c8480e455a7dae /sound
parent2e9b9a3c243b1bc1fc9d1e84fcbc32568467bf8e (diff)
downloadvexpress-lsk-281a6ac0f54052c81bbee156914459ba5a08f924.tar.gz
ALSA: usb-audio: add a workaround for the NuForce UDH-100
The NuForce UDH-100 numbers its interfaces incorrectly, which makes the interface associations come out wrong, which results in the driver erroring out with the message "Audio class v2 interfaces need an interface association". Work around this by searching for the interface association descriptor also in some other place where it might have ended up. Reported-and-tested-by: Dave Helstroom <helstroom@google.com> Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
-rw-r--r--sound/usb/card.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 803953a9bff..2da8ad75fd9 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -244,6 +244,21 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
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;
}