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[ALSA] usb-audio - use proper interval between synchronization packets

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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>
This commit is contained in:
Clemens Ladisch 2005-05-02 08:53:46 +02:00 committed by Jaroslav Kysela
parent 4dc40a3cc4
commit 1149a64fe4
1 changed files with 7 additions and 5 deletions
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12
sound/usb/usbaudio.c
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@ -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 */