From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Mack Subject: Re: Missing exactly 3 of 8 audio packets? Date: Thu, 22 Nov 2012 22:32:23 +0100 Message-ID: <50AE99E7.6080008@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-bk0-f51.google.com (mail-bk0-f51.google.com [209.85.214.51]) by alsa0.perex.cz (Postfix) with ESMTP id 95F9E2615FA for ; Thu, 22 Nov 2012 22:32:28 +0100 (CET) Received: by mail-bk0-f51.google.com with SMTP id ik5so3438739bkc.38 for ; Thu, 22 Nov 2012 13:32:28 -0800 (PST) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Daniel Griscom Cc: Alsa Developer List-Id: alsa-devel@alsa-project.org On 21.11.2012 21:13, Daniel Griscom wrote: > On to the next problem we're having with our USB audio card. Recap: > simple USB Audio Class embedded stereo audio card, running at 44.1kHz > or 48kHz, using the 3.6.6 kernel and its associated ALSA modules to > drive it, running on Jetway ND9D-2700, with an Atom D2700 and NM10 > chipset. Output of "sudo lsusb -v" for card is appended below. > > Problem: we're experiencing strange hiccups in the delivery of audio > from the motherboard to the card. At 48kHz, the motherboard should > send a 6-frame packet to the card once per high-speed microframe > (every 125us). This usually works, but sometimes there are two > closely related failures: > > 1) Once in a while (every few seconds or minutes) a single packet > will be missed > > 2) Once in a longer while (every few minutes or hours), the system > will go into a continuing error condition where three of every eight > packets are missed. > > In both cases, "missed" means that ALSA consumes the output audio > from my motherboard application, but never sends a packet to the > audio card. No USB errors, no logged messages; it just disappears. I missed that detail before. What makes you so sure ALSA actually consumes audio it never sends out? Are you sending a test pattern which is interrupted in your USB analyzer traces? Daniel