From 1149a64fe4916fe6fdc8938043a0dc9a6551ab63 Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Mon, 2 May 2005 08:53:46 +0200 Subject: [PATCH] [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 --- sound/usb/usbaudio.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c index e759b73942c..e1a648d7fff 100644 --- a/sound/usb/usbaudio.c +++ b/sound/usb/usbaudio.c @@ -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->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 @@ static int set_format(snd_usb_substream_t *subs, struct audioformat *fmt) 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 */ -- 2.20.1