Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754318Ab3H1HG3 (ORCPT ); Wed, 28 Aug 2013 03:06:29 -0400 Received: from mail-oa0-f46.google.com ([209.85.219.46]:47351 "EHLO mail-oa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752345Ab3H1HG1 (ORCPT ); Wed, 28 Aug 2013 03:06:27 -0400 MIME-Version: 1.0 In-Reply-To: <1376243970-6489-10-git-send-email-tomasz.figa@gmail.com> References: <1376243970-6489-1-git-send-email-tomasz.figa@gmail.com> <1376243970-6489-10-git-send-email-tomasz.figa@gmail.com> Date: Wed, 28 Aug 2013 09:06:27 +0200 Message-ID: Subject: Re: [PATCH 09/18] ASoC: Samsung: Do not queue cyclic buffers multiple times From: Linus Walleij To: Tomasz Figa Cc: linux-samsung-soc , "linux-arm-kernel@lists.infradead.org" , "alsa-devel@alsa-project.org" , "linux-kernel@vger.kernel.org" , linux-spi@vger.kernel.org, Dan Williams , Jaroslav Kysela , Kukjin Kim , Liam Girdwood , Mark Brown , Mike Turquette , Padmavathi Venna , Russell King , Sangbeom Kim , Takashi Iwai , Vinod Koul Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1488 Lines: 35 On Sun, Aug 11, 2013 at 7:59 PM, Tomasz Figa wrote: > The legacy S3C-DMA API required every period of a cyclic buffer to be > queued separately. After conversion of Samsung ASoC to Samsung DMA > wrappers somebody made an assumption that the same is needed for DMA > engine API, which is not true. > > In effect, Samsung ASoC DMA code was queuing the whole cyclic buffer > multiple times with a shift of one period per iteration, leading to: > a) severe memory waste - up to 13x times more DMA transfer descriptors > are allocated than needed, > b) possible memory corruption, because further cyclic buffers were out > of the original buffers, due to the offset. > > This patch fixes this problem by making the legacy S3C-DMA API use the > same semantics as DMA engine (the whole cyclic buffer is enqueued at > once) and modifying users of Samsung DMA wrappers in cyclic mode to > behave appropriately. > > Signed-off-by: Tomasz Figa > Acked-by: Linus Walleij If patch 1 thru 9 are uncontroversial now, maybe Vinod can apply these for v3.12 so we can get less noise and risk of collissions in the next merge window? Just an idea. Yours, Linus Walleij -- 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/