From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrey Gelman Subject: PROBLEM: iMX6 SSI - set up as a master of external audio codec Date: Mon, 15 Apr 2013 14:13:58 +0300 Message-ID: <516BE0F6.3060409@compulab.co.il> References: <516BDCE2.6010800@compulab.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from compulab.co.il (softlayer.compulab.co.il [50.23.254.55]) by alsa0.perex.cz (Postfix) with ESMTP id 76549265148 for ; Mon, 15 Apr 2013 13:14:01 +0200 (CEST) In-Reply-To: <516BDCE2.6010800@compulab.co.il> 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: alsa-devel@alsa-project.org, fabio.estevam@freescale.com List-Id: alsa-devel@alsa-project.org Hi, everyone ! I'm bringing up a wm8731 audio codec on an iMX6 based board. I use the slave mode, i.e. SSI outputs all the clocks towards the codec IC. I work with 3.0.35 Android kernel provided by freescale. While, generally, the playback is Ok, I face 2 issues: - cannot play back mono streams (too high rate, one speaker produces only noise) - cannot play back streams with sampling rate as low as 8kHz (the sound is accompanied by high distortion) In the mainline kernel (commits to v3.6), there is a workaround to the 1-st issue by simply removing mono support from imx-ssi.c. Similar approach would fix the 2-nd issue as well - SSI would report it does not support 8kHz sampling rate. In a later commit, this workaround has been reverted, enabling mono support back. My question is this: Is this a real limitation of SSI ? Does it support mono playback or not ? Does SSI support 8kHz sampling rate ? If yes, what could be possible reason to the distortions I get, while higher rates are played back well ? Is there a real fix to these issues, or only workarounds are available ? Thanks, Andrey Gelman