From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 29 Aug 2018 23:36:35 +0200 (CEST) Received: from outils.crapouillou.net ([89.234.176.41]:41096 "EHLO crapouillou.net" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23993946AbeH2VdUGguEp (ORCPT ); Wed, 29 Aug 2018 23:33:20 +0200 From: Paul Cercueil To: Vinod Koul , Ralf Baechle , Paul Burton Cc: od@zcrc.me, dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, Daniel Silsby , Paul Cercueil Subject: [PATCH v5 14/18] dmaengine: dma-jz4780: Further residue status fix Date: Wed, 29 Aug 2018 23:32:56 +0200 Message-Id: <20180829213300.22829-15-paul@crapouillou.net> In-Reply-To: <20180829213300.22829-1-paul@crapouillou.net> References: <20180829213300.22829-1-paul@crapouillou.net> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1535578399; bh=DlDnbpEDKjFmeiXU/E5155BZtoBzBOLXoOhxAu0xxIY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=wOVcYoIauOs39k6KCN4TYJGyWZinvJkH6LvT0vQlMztSaR6+sYg9kOtMXK4Zo/TgC4KYbRZ3y6DJfGWYkFStdBoYvoxNZXk7qpmkbqRP/b1AmwklqHUO8E1vzVWnaFahZcaDknhDgpQWa/wS3SrInWpvi2Rl4I+phzHD+/DEbdQ= Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 65793 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: paul@crapouillou.net Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips 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 Signed-off-by: Paul Cercueil Tested-by: Mathieu Malaterre --- Notes: v2: No change v3: No change v4: Add my Signed-off-by v5: No change 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 d3b915ec8a09..b73d96166637 100644 --- a/drivers/dma/dma-jz4780.c +++ b/drivers/dma/dma-jz4780.c @@ -653,7 +653,7 @@ 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