[ALSA] usb-audio - use proper interval between synchronization packets
USB generic driver
Add sanity checks when reading the bRefresh value, and actually use it
for the synchronization packets instead of polling at 1000 Hz.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index e759b73..e1a648d 100644
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -1051,10 +1051,7 @@
u->urb->pipe = subs->syncpipe;
u->urb->transfer_flags = URB_ISO_ASAP;
u->urb->number_of_packets = u->packets;
- if (snd_usb_get_speed(subs->dev) == USB_SPEED_HIGH)
- u->urb->interval = 8;
- else
- u->urb->interval = 1;
+ u->urb->interval = 1 << subs->syncinterval;
u->urb->context = u;
u->urb->complete = snd_usb_complete_callback(snd_complete_sync_urb);
}
@@ -1272,7 +1269,12 @@
subs->syncpipe = usb_rcvisocpipe(dev, ep);
else
subs->syncpipe = usb_sndisocpipe(dev, ep);
- subs->syncinterval = get_endpoint(alts, 1)->bRefresh;
+ if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
+ get_endpoint(alts, 1)->bRefresh >= 1 &&
+ get_endpoint(alts, 1)->bRefresh <= 9)
+ subs->syncinterval = get_endpoint(alts, 1)->bRefresh;
+ else
+ subs->syncinterval = 1;
}
/* always fill max packet size */
