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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 8E8D3C6778C for ; Tue, 3 Jul 2018 12:33:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3842C2084D for ; Tue, 3 Jul 2018 12:33:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=crapouillou.net header.i=@crapouillou.net header.b="nyjY6e6E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3842C2084D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=crapouillou.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 S932248AbeGCMcp (ORCPT ); Tue, 3 Jul 2018 08:32:45 -0400 Received: from outils.crapouillou.net ([89.234.176.41]:49726 "EHLO crapouillou.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932181AbeGCMcn (ORCPT ); Tue, 3 Jul 2018 08:32:43 -0400 From: Paul Cercueil To: Vinod Koul , Rob Herring , Mark Rutland , Ralf Baechle , Paul Burton , James Hogan , Zubair Lutfullah Kakakhel Cc: Mathieu Malaterre , Daniel Silsby , dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org Subject: [PATCH 11/14] dmaengine: dma-jz4780: Further residue status fix Date: Tue, 3 Jul 2018 14:32:11 +0200 Message-Id: <20180703123214.23090-12-paul@crapouillou.net> In-Reply-To: <20180703123214.23090-1-paul@crapouillou.net> References: <20180703123214.23090-1-paul@crapouillou.net> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1530621161; bh=enkQAEhOU5uNiPVbgK7vMWl7oouDaqOl2/Xy8HlDqpM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=nyjY6e6Ej1girbg211tllekja9eKNp2bLJzTNNLkvrVOE/JEpOn8A2OIfVYp15mrhDYYYCMdlf0ELUNe38Ez7c3bsIdO5Zr3BrrTcW+0wZNhzG7A+JVnIbYaEeqbYvsTaGywCQrXANQzBADE2aLEm0/AdHD3keFyQW3ycrGAqUM= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Daniel Silsby Func jz4780_dma_desc_residue() expects the index to the next hw descriptor as its last parameter. Caller func jz4780_dma_tx_status(), however, applied modulus before passing it. When the current hw descriptor was last in the list, the index passed became zero. The resulting excess of reported residue especially caused problems with cyclic DMA transfer clients, i.e. ALSA AIC audio output, which rely on this for determining current DMA location within buffer. Combined with the recent and related residue-reporting fixes, spurious ALSA audio underruns on jz4770 hardware are now fixed. Signed-off-by: Daniel Silsby --- drivers/dma/dma-jz4780.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c index 64270d53ba57..690b853977b2 100644 --- a/drivers/dma/dma-jz4780.c +++ b/drivers/dma/dma-jz4780.c @@ -647,7 +647,7 @@ static enum dma_status jz4780_dma_tx_status(struct dma_chan *chan, to_jz4780_dma_desc(vdesc), 0); } else if (cookie == jzchan->desc->vdesc.tx.cookie) { txstate->residue = jz4780_dma_desc_residue(jzchan, jzchan->desc, - (jzchan->curr_hwdesc + 1) % jzchan->desc->count); + jzchan->curr_hwdesc + 1); } else txstate->residue = 0; -- 2.18.0