ALSA: usb-audio: store protocol version in struct audioformat

Instead of reading bInterfaceProtocol from the descriptor whenever it's
needed, store this value in the audioformat structure.  Besides
simplifying some code, this will allow us to correctly handle vendor-
specific devices where the descriptors are marked with other values.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

1 files changed, 1 insertions, 3 deletions

diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index 3a2ce390e278..86f80c60b21f 100644
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -407,9 +407,7 @@ int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
                              struct usb_host_interface *alts,
                              struct audioformat *fmt, int rate)
 {
-        struct usb_interface_descriptor *altsd = get_iface_desc(alts);
-
-        switch (altsd->bInterfaceProtocol) {
+        switch (fmt->protocol) {
         case UAC_VERSION_1:
         default:
                 return set_sample_rate_v1(chip, iface, alts, fmt, rate);