From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clemens Ladisch Subject: Re: How to use implicit feedback with full duplex? Date: Wed, 06 Feb 2013 21:13:29 +0100 Message-ID: <5112B969.50905@ladisch.de> References: <51116F36.9040106@ladisch.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from out5-smtp.messagingengine.com (out5-smtp.messagingengine.com [66.111.4.29]) by alsa0.perex.cz (Postfix) with ESMTP id 07C2A260818 for ; Wed, 6 Feb 2013 21:14:27 +0100 (CET) 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: Eldad Zack Cc: alsa-devel@alsa-project.org, Daniel Mack List-Id: alsa-devel@alsa-project.org Eldad Zack wrote: > On Tue, 5 Feb 2013, Clemens Ladisch wrote: >> I thought I'd try to use implicit feedback with my simple audio device: >> [...] >> This works fine when playing something: > ... >> But when I then try to record at the same time, the driver refuses to >> configure the input endpoint (to the only format, which is already set): >> And despite that "alreay in use" check, the input endpoint is affected >> so much that playback breaks. >> >> Is full duplex supposed to work? Does it work with other devices? > > This is probably a "yes, but" :) > I use my device mostly full duplex, but with jack opening both > playback and capture at the same time. > > I assume you are opening two different streams, one for playback and > one for capture. Jack *also* uses two different streams, but it opens them at the same time. > Can you try using jackd -d alsa -d hw:x with the device and see if that > works for you? That works. This means that there is a race condition in the driver, or that the different open/hw_params/prepare order trips it up. Anyway, I feel safe now to enable implicit feedback for other devices. Regards, Clemens