From owner-svn-src-all@freebsd.org  Wed Nov  9 07:09:28 2016
Return-Path: <owner-svn-src-all@freebsd.org>
Delivered-To: svn-src-all@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 77FD7C3797C;
 Wed,  9 Nov 2016 07:09:28 +0000 (UTC)
 (envelope-from hselasky@FreeBSD.org)
Received: from repo.freebsd.org (repo.freebsd.org
 [IPv6:2610:1c1:1:6068::e6a:0])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 49AECCBB;
 Wed,  9 Nov 2016 07:09:28 +0000 (UTC)
 (envelope-from hselasky@FreeBSD.org)
Received: from repo.freebsd.org ([127.0.1.37])
 by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id uA979RGf035473;
 Wed, 9 Nov 2016 07:09:27 GMT (envelope-from hselasky@FreeBSD.org)
Received: (from hselasky@localhost)
 by repo.freebsd.org (8.15.2/8.15.2/Submit) id uA979RAZ035472;
 Wed, 9 Nov 2016 07:09:27 GMT (envelope-from hselasky@FreeBSD.org)
Message-Id: <201611090709.uA979RAZ035472@repo.freebsd.org>
X-Authentication-Warning: repo.freebsd.org: hselasky set sender to
 hselasky@FreeBSD.org using -f
From: Hans Petter Selasky <hselasky@FreeBSD.org>
Date: Wed, 9 Nov 2016 07:09:27 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r308461 - head/sys/dev/sound/usb
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-all@freebsd.org
X-Mailman-Version: 2.1.23
Precedence: list
List-Id: "SVN commit messages for the entire src tree \(except for &quot;
 user&quot; and &quot; projects&quot; \)" <svn-src-all.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-all>,
 <mailto:svn-src-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all/>
List-Post: <mailto:svn-src-all@freebsd.org>
List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-all>,
 <mailto:svn-src-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 09 Nov 2016 07:09:28 -0000

Author: hselasky
Date: Wed Nov  9 07:09:27 2016
New Revision: 308461
URL: https://svnweb.freebsd.org/changeset/base/308461

Log:
  Allow higher sample rates to have more jitter than lower ones.
  
  PR:		208791
  MFC after:	3 days

Modified:
  head/sys/dev/sound/usb/uaudio.c

Modified: head/sys/dev/sound/usb/uaudio.c
==============================================================================
--- head/sys/dev/sound/usb/uaudio.c	Wed Nov  9 06:47:29 2016	(r308460)
+++ head/sys/dev/sound/usb/uaudio.c	Wed Nov  9 07:09:27 2016	(r308461)
@@ -2079,6 +2079,8 @@ uaudio_chan_play_sync_callback(struct us
 		 * recording channel:
 		 */
 		if (ch->priv_sc->sc_rec_chan.num_alt == 0) {
+			int32_t jitter_max = howmany(sample_rate, 16000);
+
 			/*
 			 * Range check the jitter values to avoid
 			 * bogus sample rate adjustments. The expected
@@ -2087,12 +2089,11 @@ uaudio_chan_play_sync_callback(struct us
 			 * mandates this requirement. Refer to chapter
 			 * 5.12.4.2 about feedback.
 			 */
-			if (temp > sample_rate)
-				ch->jitter_curr = 1;
-			else if (temp < sample_rate)
-				ch->jitter_curr = -1;
-			else
-				ch->jitter_curr = 0;
+			ch->jitter_curr = temp - sample_rate;
+			if (ch->jitter_curr > jitter_max)
+				ch->jitter_curr = jitter_max;
+			else if (ch->jitter_curr < -jitter_max)
+				ch->jitter_curr = -jitter_max;
 		}
 		ch->feedback_rate = temp;
 		break;