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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 572D1C433F5 for ; Mon, 27 Aug 2018 16:22:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 03737208AF for ; Mon, 27 Aug 2018 16:22:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 03737208AF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lucaceresoli.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727056AbeH0UJ6 (ORCPT ); Mon, 27 Aug 2018 16:09:58 -0400 Received: from srv-hp10-72.netsons.net ([94.141.22.72]:39576 "EHLO srv-hp10-72.netsons.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726731AbeH0UJ5 (ORCPT ); Mon, 27 Aug 2018 16:09:57 -0400 Received: from [109.168.11.45] (port=55498 helo=[192.168.101.125]) by srv-hp10.netsons.net with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.91) (envelope-from ) id 1fuKHj-00CWMN-UM; Mon, 27 Aug 2018 18:22:35 +0200 Subject: Re: [PATCH 1/1] axi-i2s: set period size register To: Lars-Peter Clausen , alsa-devel@alsa-project.org Cc: Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , linux-kernel@vger.kernel.org, Michal Simek References: <20180824160430.10222-1-luca@lucaceresoli.net> <20180824160430.10222-2-luca@lucaceresoli.net> From: Luca Ceresoli Message-ID: <263e42b4-75a3-183c-894b-e485e387eccf@lucaceresoli.net> Date: Mon, 27 Aug 2018 18:22:37 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - srv-hp10.netsons.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lucaceresoli.net X-Get-Message-Sender-Via: srv-hp10.netsons.net: authenticated_id: luca@lucaceresoli.net X-Authenticated-Sender: srv-hp10.netsons.net: luca@lucaceresoli.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, thanks for your feedback. [Adding Michal Simek (Xilinx maintainer) in Cc] On 27/08/2018 14:27, Lars-Peter Clausen wrote: > On 08/24/2018 06:04 PM, Luca Ceresoli wrote: >> The default value of the PERIOD_LEN register is 0 and results in >> axi-i2s keeping TLAST always asserted in its AXI Stream output. >> >> When the AXI Stream is sent to a Xilinx AXI-DMA, this results in the >> DMA generating an interrupt flood and ALSA produce a corrupted >> recording. This is because AXI-DMA raises an interrupt whenever TLAST >> is active. >> >> Fix by setting the PERIOD_LEN register as soon as the period is >> known. This way TLAST is emitted once per period, and the DMA raises >> interrupts correctly. > > The patch looks OK. But I'd prefer not to merge it if possible. > > We've done some early experiments with the Xilinx AXI-DMA, but it turned out > to be to unreliable and we've abandoned support for it. One of the more > critical issues was that you can't abort a DMA transfer. That means when > audio capture is stopped the DMA will halt, but not complete the current > transfer. Then when the next audio capture start the DMA will continue with > the previous transfer. The observed effect of this was that the system would > just crash randomly (Presumably due to memory corruption). Strange. I have done many capture experiments with arecord and didn't run into such bad issues. I only have a much less serious problem (garbage or old samples in the first few buffers), but no crashes. Michal, are you aware of these problems? > Have you considered using the ADI AXI-DMAC? That should work just fine. Not until today, because AXI-DMA is working here. I'd like to better understand what's going on before changing an IP that is working. Do you have additional details about your setup? How do you run your tests? Regards, -- Luca