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Commit 1149a64f authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Jaroslav Kysela
Browse files

[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: default avatarClemens Ladisch <clemens@ladisch.de>
parent 4dc40a3c

sound/usb/usbaudio.c

+7 −5
Original line number Original line Diff line number Diff line
@@ -1051,10 +1051,7 @@ static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_by 
			u->urb->pipe = subs->syncpipe;

			u->urb->pipe = subs->syncpipe;

			u->urb->transfer_flags = URB_ISO_ASAP;

			u->urb->transfer_flags = URB_ISO_ASAP;

			u->urb->number_of_packets = u->packets;

			u->urb->number_of_packets = u->packets;

			if (snd_usb_get_speed(subs->dev) == USB_SPEED_HIGH)

			u->urb->interval = 1 << subs->syncinterval;

				u->urb->interval = 8;

			else

				u->urb->interval = 1;

			u->urb->context = u;

			u->urb->context = u;

			u->urb->complete = snd_usb_complete_callback(snd_complete_sync_urb);

			u->urb->complete = snd_usb_complete_callback(snd_complete_sync_urb);

		}

		}
@@ -1272,7 +1269,12 @@ static int set_format(snd_usb_substream_t *subs, struct audioformat *fmt) 
			subs->syncpipe = usb_rcvisocpipe(dev, ep);

			subs->syncpipe = usb_rcvisocpipe(dev, ep);

		else

		else

			subs->syncpipe = usb_sndisocpipe(dev, ep);

			subs->syncpipe = usb_sndisocpipe(dev, ep);

		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;

			subs->syncinterval = get_endpoint(alts, 1)->bRefresh;

		else

			subs->syncinterval = 1;

	}

	}





	/* always fill max packet size */

	/* always fill max packet size */