From f408c69c42cbe286dfd8184c4ecf258be7afa5e6 Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Mon, 11 Mar 2013 20:15:34 +0100 Subject: [PATCH] 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 Signed-off-by: Clemens Ladisch Signed-off-by: Takashi Iwai --- sound/usb/card.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/sound/usb/card.c b/sound/usb/card.c index 803953a9bff33..2da8ad75fd96c 100644 --- 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; -- 2.39.5