From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752837AbbIZMjI (ORCPT ); Sat, 26 Sep 2015 08:39:08 -0400 Received: from smtpbgau2.qq.com ([54.206.34.216]:57323 "EHLO smtpbgau2.qq.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752751AbbIZMjH (ORCPT ); Sat, 26 Sep 2015 08:39:07 -0400 X-QQ-mid: bizesmtp11t1443271132t862t30 X-QQ-SSF: 01100000000000F0FF42 X-QQ-FEAT: 2rctQ1BDGQWpBcEd7cPoHLlvBXCxOi6NiArtSTeOLAPzyoUV/viNcvIeH5U3Y Zr0Qe2eEoCkCRs0ekoO492BvW4CZO4u4VAXUWNa5lhFlnbgodB5oRxzNddWVi/dyYf8AwuM a6fA071QP6Yai8ueDHrN7Cba64KTs8enweyJsoJSaKC6tYHATAbbRs32/t0h5WxYdveANC/ 99TgDi1cZ0eULdfjMSvadK92omvyFmVM0va5WlGaz0muTHjYqa6yWmIm/MslMz/Q= X-QQ-GoodBg: 0 From: "yitian" To: , , , Cc: , Subject: [PATCH 1/1] dmaengine: dw: resolve recursion lock when audio playback Date: Sat, 26 Sep 2015 20:38:47 +0800 Message-ID: <025c01d0f858$4d19c790$e74d56b0$@tangramtek.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 15.0 Thread-Index: AdD4V+wOQfSqgTtdRqCE2K537VWNSQ== Content-Language: zh-cn X-QQ-SENDSIZE: 520 X-QQ-Bgrelay: 1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org when audio playback is running, user space will call snd_pcm_lib_write1() function, it will first get pcm stream lock, after that it may call function snd_pcm_update_hw_ptr(), the call stack will be as below: snd_pcm_lib_write1 <-- got pcm stream lock --> snd_pcm_update_hw_ptr --> dwc_tx_status --> dwc_scan_descriptors --> callback --> dmaengine_pcm_dma_complete --> snd_pcm_period_elapsed <-- get stream lock again recursion lock occurs in snd_pcm_period_elapsed function. remove dwc_scan_descriptors from dwc_tx_status can fix this issue. Signed-off-by: Yitian Bu --- drivers/dma/dw/core.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c index cf1c87f..5341b44 100644 --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -1078,11 +1078,7 @@ dwc_tx_status(struct dma_chan *chan, ret = dma_cookie_status(chan, cookie, txstate); if (ret == DMA_COMPLETE) return ret; - - dwc_scan_descriptors(to_dw_dma(chan->device), dwc); - - ret = dma_cookie_status(chan, cookie, txstate); - if (ret != DMA_COMPLETE) + else dma_set_residue(txstate, dwc_get_residue(dwc)); if (dwc->paused && ret == DMA_IN_PROGRESS) -- 1.7.12.4 Yitian Best Regards