From mboxrd@z Thu Jan 1 00:00:00 1970 From: Liam Girdwood Subject: Re: [PATCH 0/2] ASoC: davinci: ping-pong buffers for mcasp on da850evm Date: Thu, 19 May 2011 12:08:09 +0100 Message-ID: <4DD4FA19.70107@ti.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from comal.ext.ti.com (comal.ext.ti.com [198.47.26.152]) by alsa0.perex.cz (Postfix) with ESMTP id C4D6A103847 for ; Thu, 19 May 2011 13:08:13 +0200 (CEST) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Ben Gardiner Cc: "alsa-devel@alsa-project.org" , Subhasish Ghosh , Mark Brown , "Nori, Sekhar" , "davinci-linux-open-source@linux.davincidsp.com" , Troy Kisky List-Id: alsa-devel@alsa-project.org On 18/05/11 14:27, Ben Gardiner wrote: > davinci-i2s enables the use of ping-pong buffers by copying the sram sizes > specified by platform data into the dma params used by davinci-pcm. > > This patch series first implements that same behaviour in davinic-mcasp > and then specified sram sizes and eventq's for da850evm. > > To achieve the use of ping-pong buffers at runtime this patch depends also > on the conversion of da850's SRAM allocator to the "Share RAM" region from > the "ARM Local RAM" region -- originally proposed by Subhasish Ghosh[1] and > recently reposted by myself [2]. > > This is because the "ARM Local RAM" region currently used by the da850 SRAM > allocator is not addressable by the EDMA. The resulting behaviour, when > ping-pong buffers are used by davinci-pcm, is that playback produces silence > and capture acquires silence. > > However, there is no change in behaviour for da850evm build with the in-tree > defconfig since suspend allocates SRAM which prevents a successful allocation > of 8K by davinci-pcm and thus the behaviour falls back to the usual scheme. > > In the case of da850evm builds where CONFIG_SUSPEND is not set, playback > will produce silence and capture will acquire silence until such time as the > patches to change the da850 SRAM allocator to the "Shared RAM" region are > merged. > > [1] http://article.gmane.org/gmane.linux.kernel/1098928 > [2] http://article.gmane.org/gmane.linux.ports.arm.kernel/117261 > > Ben Gardiner (2): > ASoC: davinci-mcasp: enable ping-pong SRAM buffers > davinci: da850evm: enable mcasp ping-pong buffers and eventq's > > arch/arm/mach-davinci/board-da850-evm.c | 5 ++++- > sound/soc/davinci/davinci-mcasp.c | 2 ++ > 2 files changed, 6 insertions(+), 1 deletions(-) > Both Acked-by: Liam Girdwood