[ALSA] usb-audio - fix synchronization packet interval with Audigy 2 NX
USB generic driver
When a device does not provide the bRefresh field in its audio endpoint
descriptors, use the bInterval field instead.
Furthermore, increase the number of sync URBs for better queueing.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index 076da19..a82412b 100644
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -98,7 +98,7 @@
#define MAX_PACKS 10
#define MAX_PACKS_HS (MAX_PACKS * 8) /* in high speed mode */
#define MAX_URBS 5 /* max. 20ms long packets */
-#define SYNC_URBS 2 /* always two urbs for sync */
+#define SYNC_URBS 4 /* always four urbs for sync */
#define MIN_PACKS_URB 1 /* minimum 1 packet per urb */
typedef struct snd_usb_substream snd_usb_substream_t;
@@ -1240,8 +1240,13 @@
get_endpoint(alts, 1)->bRefresh >= 1 &&
get_endpoint(alts, 1)->bRefresh <= 9)
subs->syncinterval = get_endpoint(alts, 1)->bRefresh;
- else
+ else if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
subs->syncinterval = 1;
+ else if (get_endpoint(alts, 1)->bInterval >= 1 &&
+ get_endpoint(alts, 1)->bInterval <= 16)
+ subs->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
+ else
+ subs->syncinterval = 3;
}
/* always fill max packet size */
