Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751522AbdF0OgA (ORCPT ); Tue, 27 Jun 2017 10:36:00 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55600 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752361AbdF0OOO (ORCPT ); Tue, 27 Jun 2017 10:14:14 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matthias Reichl , Martin Sperl , Clive Messer , Eric Anholt , Vinod Koul , Amit Pundir Subject: [PATCH 4.9 40/44] dmaengine: bcm2835: Fix cyclic DMA period splitting Date: Tue, 27 Jun 2017 16:12:52 +0200 Message-Id: <20170627141110.682080812@linuxfoundation.org> X-Mailer: git-send-email 2.13.2 In-Reply-To: <20170627141107.865578528@linuxfoundation.org> References: <20170627141107.865578528@linuxfoundation.org> User-Agent: quilt/0.65 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: 1650 Lines: 47 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthias Reichl commit 2201ac6129fa162ac24da089a034bb0971648ebb upstream. The code responsible for splitting periods into chunks that can be handled by the DMA controller missed to update total_len, the number of bytes processed in the current period, when there are more chunks to follow. Therefore total_len was stuck at 0 and the code didn't work at all. This resulted in a wrong control block layout and audio issues because the cyclic DMA callback wasn't executing on period boundaries. Fix this by adding the missing total_len update. Signed-off-by: Matthias Reichl Signed-off-by: Martin Sperl Tested-by: Clive Messer Reviewed-by: Eric Anholt Signed-off-by: Vinod Koul Signed-off-by: Amit Pundir Signed-off-by: Greg Kroah-Hartman --- drivers/dma/bcm2835-dma.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/dma/bcm2835-dma.c +++ b/drivers/dma/bcm2835-dma.c @@ -251,8 +251,11 @@ static void bcm2835_dma_create_cb_set_le */ /* have we filled in period_length yet? */ - if (*total_len + control_block->length < period_len) + if (*total_len + control_block->length < period_len) { + /* update number of bytes in this period so far */ + *total_len += control_block->length; return; + } /* calculate the length that remains to reach period_length */ control_block->length = period_len - *total_len;