ALSA: usb: USB3 SuperSpeed sound support

This is V2 of the patch, after feedback from Clemens and Daniel.

This patch adds SuperSpeed support to the USB drivers under sound/. It adds
tests for USB_SPEED_SUPER to the appropriate places that check for the USB
speed.

This patch has been tested with our SS USB3 device emulating a set of Yamaha
speakers and a Logitech microphone, but with the descriptors modified to add
USB3 support. It has also been tested with the real speakers and microphone,
to make sure that USB2 devices still work.

Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: Daniel Mack <daniel@caiaq.de>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 11 insertions, 6 deletions

diff --git a/sound/usb/helper.c b/sound/usb/helper.c
index d48d6f8f6ac9..f280c1903c25 100644
--- a/sound/usb/helper.c
+++ b/sound/usb/helper.c
@@ -103,11 +103,16 @@ int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
 unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,
                                          struct usb_host_interface *alts)
 {
-        if (snd_usb_get_speed(chip->dev) == USB_SPEED_HIGH &&
-            get_endpoint(alts, 0)->bInterval >= 1 &&
-            get_endpoint(alts, 0)->bInterval <= 4)
-                return get_endpoint(alts, 0)->bInterval - 1;
-        else
-                return 0;
+        switch (snd_usb_get_speed(chip->dev)) {
+        case USB_SPEED_HIGH:
+        case USB_SPEED_SUPER:
+                if (get_endpoint(alts, 0)->bInterval >= 1 &&
+                    get_endpoint(alts, 0)->bInterval <= 4)
+                        return get_endpoint(alts, 0)->bInterval - 1;
+                break;
+        default:
+                break;
+        }
+        return 0;
 }