From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752580AbdBTTIr (ORCPT ); Mon, 20 Feb 2017 14:08:47 -0500 Received: from mail.horus.com ([78.46.148.228]:33482 "EHLO mail.horus.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751364AbdBTTIp (ORCPT ); Mon, 20 Feb 2017 14:08:45 -0500 X-Greylist: delayed 445 seconds by postgrey-1.27 at vger.kernel.org; Mon, 20 Feb 2017 14:08:44 EST Date: Mon, 20 Feb 2017 20:01:16 +0100 From: Matthias Reichl To: Vinod Koul , Stephen Warren , Lee Jones , Eric Anholt Cc: Martin Sperl , Clive Messer , dmaengine@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [RESEND PATCH] dmaengine: bcm2835: Fix cyclic DMA period splitting Message-ID: <20170220190115.GB4170@camel2.lan> Mail-Followup-To: Matthias Reichl , Vinod Koul , Stephen Warren , Lee Jones , Eric Anholt , Martin Sperl , Clive Messer , dmaengine@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- drivers/dma/bcm2835-dma.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c index 80d35f7..599c218 100644 --- a/drivers/dma/bcm2835-dma.c +++ b/drivers/dma/bcm2835-dma.c @@ -253,8 +253,11 @@ static void bcm2835_dma_create_cb_set_length( */ /* 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; -- 2.1.4