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 813EDECDFB8 for ; Wed, 18 Jul 2018 18:21:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3579820850 for ; Wed, 18 Jul 2018 18:21:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=crapouillou.net header.i=@crapouillou.net header.b="bMy1duDP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3579820850 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 S1731054AbeGRTAI (ORCPT ); Wed, 18 Jul 2018 15:00:08 -0400 Received: from outils.crapouillou.net ([89.234.176.41]:43356 "EHLO crapouillou.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730810AbeGRTAI (ORCPT ); Wed, 18 Jul 2018 15:00:08 -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 , Paul Cercueil , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org Subject: [PATCH v2 13/17] dmaengine: dma-jz4780: Further residue status fix Date: Wed, 18 Jul 2018 20:20:19 +0200 Message-Id: <20180718182023.8182-14-paul@crapouillou.net> In-Reply-To: <20180718182023.8182-1-paul@crapouillou.net> References: <20180718182023.8182-1-paul@crapouillou.net> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1531938060; bh=wLtygciA8kesCct7e/GjoIaL5q5d2hxkrc9IVMEKpJU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=bMy1duDPsmfp1EUXgdduwxtBlliTDpQqHKeT9aQ+Im40am95G8XWegjaBP+DPZ4ByoeKG2AGvoLW8yNmwL0AmQwKBd+lU+JcSX869majNDMUq8+5JBZKOlqKFVzi2X/sRL0ozFRkf56ICQDrZ9uLXVWea6ulLOyXa3v0bcCmKxc= 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 Tested-by: Mathieu Malaterre --- drivers/dma/dma-jz4780.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) v2: No change diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c index 78849131c81d..b9db539a5b34 100644 --- a/drivers/dma/dma-jz4780.c +++ b/drivers/dma/dma-jz4780.c @@ -651,7 +651,7 @@ 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; -- 2.11.0