Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932691AbbHNRn3 (ORCPT ); Fri, 14 Aug 2015 13:43:29 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51027 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755280AbbHNRm7 (ORCPT ); Fri, 14 Aug 2015 13:42:59 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Krzysztof Kozlowski , gabriel@unseen.is, Marek Szyprowski , Lars-Peter Clausen , Vinod Koul Subject: [PATCH 4.1 22/84] dmaengine: pl330: Really fix choppy sound because of wrong residue calculation Date: Fri, 14 Aug 2015 10:41:50 -0700 Message-Id: <20150814174210.893007267@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150814174210.214822912@linuxfoundation.org> References: <20150814174210.214822912@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2216 Lines: 58 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Krzysztof Kozlowski commit 5dd90e5b91e0f5c925b12b132c7cd27538870256 upstream. When pl330 driver was used during sound playback, after some time or after a number of plays the sound became choppy or totally noisy. For example on Odroid XU3 board the first four executions of aplay with small WAVE worked fine, but fifth was unrecognizable with errors: $ aplay /usr/share/sounds/alsa/Front_Right.wava underrun!!! (at least 0.095 ms long) Issue was caused by wrong residue reported by pl330 driver to pcm_dmaengine for its cyclic dma transfers. The pl330_tx_status(), residue reporting function, used a "last" flag in a descriptor to indicate that there is no more data to send. The pl330_tx_submit() iterated over descriptors trying to remove this flag from them and then mark last descriptor as "last". However when iterating it actually removed the flag not from descriptors but always from last of it (and then reset it). Thus effectively once some descriptor was marked as last, then it stayed like this forever causing residue to be reported too low. Signed-off-by: Krzysztof Kozlowski Fixes: aee4d1fac887 ("dmaengine: pl330: improve pl330_tx_status() function") Reported-by: gabriel@unseen.is Suggested-by: Marek Szyprowski Tested-by: Lars-Peter Clausen Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/dma/pl330.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2328,7 +2328,7 @@ static dma_cookie_t pl330_tx_submit(stru desc->txd.callback = last->txd.callback; desc->txd.callback_param = last->txd.callback_param; } - last->last = false; + desc->last = false; dma_cookie_assign(&desc->txd); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/