From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF4F3C433FE for ; Tue, 8 Dec 2020 13:31:05 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 716FD23AA9 for ; Tue, 8 Dec 2020 13:31:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 716FD23AA9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id DFC2516EB; Tue, 8 Dec 2020 14:30:11 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz DFC2516EB DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1607434262; bh=SljcaB0SaYf6LSgvIaMbxc2bAgzxpwEak7IehWNs3mw=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=pMj84eW7OVPSd3/KHeV6of6m90hL66UWMod5M3W8gCL+1NvnjUFySQguKYMoIEnBP BA+VSGYJLhSLP67pHsX17juVpJn8LDqoaCTA4jUV3puIZgQuzvBpADrPwd0ZWTcJE7 ow3+Yz+ZbFHL0W8awT4DRAB5rgDSXthU6jBNnFOU= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 414E9F80164; Tue, 8 Dec 2020 14:30:11 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 4988DF8019D; Tue, 8 Dec 2020 14:30:09 +0100 (CET) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id C6ADFF800E1 for ; Tue, 8 Dec 2020 14:30:03 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz C6ADFF800E1 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id BA343AC9A; Tue, 8 Dec 2020 13:30:02 +0000 (UTC) Date: Tue, 08 Dec 2020 14:30:02 +0100 Message-ID: From: Takashi Iwai To: Ben Bell Subject: Re: Behringer WING usb audio - cyclic xruns dependent on periods/buffers In-Reply-To: <20201205144406.854292C16C@relay2.suse.de> References: <20201126180612.E3E0CF80166@alsa1.perex.cz> <20201128093612.48C0CF80166@alsa1.perex.cz> <20201203200633.CC66A2C16F@relay2.suse.de> <20201205144406.854292C16C@relay2.suse.de> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Cc: alsa-devel@alsa-project.org X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On Sat, 05 Dec 2020 15:43:56 +0100, Ben Bell wrote: > > > > Like I said in the initial email, it feels like some sort of clock drift > > > problem, where we're managing very slowly to collect more samples than > > > we're reading -- to the tune of about 1 extra every few cycles -- and > > > nothing on the consumer side is ever managing to compensate for that. > > > I'm not even sure how that sort of drift would be possible though. Seems > > > surprising. > [...] > > > At least you can try the latest patch set destined for 5.11, which > > should improve the cases for the implicit feedback. > > Aha! This actually was the key piece of information I needed. I haven't > tried 5.11 or the latest patch set yet, but googling "implicit feedback" > and learning abobut it led me to conclude that the Wing needs an entry in > the quirks list in set_sync_ep_implicit_fb_quirk to properly enable it: > > --- sound/usb/pcm.c.orig 2020-11-22 23:36:08.000000000 +0000 > +++ sound/usb/pcm.c 2020-12-05 08:40:21.639600074 +0000 > @@ -340,6 +345,7 @@ > ep = 0x81; > ifnum = 3; > goto add_sync_ep_from_ifnum; > + case USB_ID(0x1397, 0x050b): /* Behringer Wing */ > case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */ > case USB_ID(0x0763, 0x2081): > > > A week's worth of debugging and learning yielded a one line patch ;) That's a interesting piece of information :) Could you give lsusb -v output of the device? With the latest patch set, the driver can set up the implicit feedback mode automatically in certain cases. I'm not sure whether Behringer device follows that pattern. If not, we'd need to add the quirk manually. thanks, Takashi