From 765e8db078e63fdc076fcf6024c15d3b7b955746 Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Mon, 10 Aug 2009 10:07:35 +0200 Subject: [PATCH] sound: usb-audio: do not make URBs longer than sync packet interval Using more packets in one URB do avoid interrupts does not make sense when we have a sync pipe whose packets generate interrupts more often. Therefore, limit the URB size to the synchronization packet interval. Signed-off-by: Clemens Ladisch Signed-off-by: Takashi Iwai --- sound/usb/usbaudio.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c index 44b9cdc8a83b..fa3f7a1dc5e1 100644 --- a/sound/usb/usbaudio.c +++ b/sound/usb/usbaudio.c @@ -1083,6 +1083,8 @@ static int init_substream_urbs(struct snd_usb_substream *subs, unsigned int peri } else urb_packs = 1; urb_packs *= packs_per_ms; + if (subs->syncpipe) + urb_packs = min(urb_packs, 1 << subs->syncinterval); /* decide how many packets to be used */ if (is_playback) {