From 17d1e3cfca365bd0ef9774a768fcd673602181b3 Mon Sep 17 00:00:00 2001
From: Clemens Ladisch <clemens@ladisch.de>
Date: Fri, 12 Aug 2005 08:28:27 +0200
Subject: [PATCH] --- yaml --- r: 6521 b: refs/heads/master c:
 d6db392e9235c48bb945624798e9beede7b85b12 h: refs/heads/master i:   6519:
 0e9518384f40f274e48a4a9f29811d2861add698 v: v3

---
 [refs]                     |  2 +-
 trunk/sound/usb/usbaudio.c | 10 +++++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index b99ee6cd70f0..af48fc46af2d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 15a24c0778e9bdd48d8e1cf60a263837b5c30ed5
+refs/heads/master: d6db392e9235c48bb945624798e9beede7b85b12
diff --git a/trunk/sound/usb/usbaudio.c b/trunk/sound/usb/usbaudio.c
index 9e38d3d1322a..d28106e390c4 100644
--- a/trunk/sound/usb/usbaudio.c
+++ b/trunk/sound/usb/usbaudio.c
@@ -938,7 +938,15 @@ static int init_substream_urbs(snd_usb_substream_t *subs, unsigned int period_by
 
 	/* decide how many packets to be used */
 	if (is_playback) {
-		total_packs = (period_bytes + maxsize - 1) / maxsize;
+		unsigned int minsize;
+		/* determine how small a packet can be */
+		minsize = (subs->freqn >> (16 - subs->datainterval))
+			  * (frame_bits >> 3);
+		/* with sync from device, assume it can be 25% lower */
+		if (subs->syncpipe)
+			minsize -= minsize >> 2;
+		minsize = max(minsize, 1u);
+		total_packs = (period_bytes + minsize - 1) / minsize;
 		if (total_packs < 2 * MIN_PACKS_URB)
 			total_packs = 2 * MIN_PACKS_URB;
 	} else {