Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755284Ab3J2Mxp (ORCPT ); Tue, 29 Oct 2013 08:53:45 -0400 Received: from ch1ehsobe002.messaging.microsoft.com ([216.32.181.182]:13418 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755195Ab3J2Mxn convert rfc822-to-8bit (ORCPT ); Tue, 29 Oct 2013 08:53:43 -0400 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI X-SpamScore: 0 X-BigFish: VS0(zz98dIzz1f42h208ch1ee6h1de0h1fdah2073h1202h1e76h1d1ah1d2ah1fc6hzz1de098h8275dh1de097hz2dh2a8h839h8e2h8e3h947hd24hf0ah1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh162dh1631h1758h18deh18e1h1946h19b5h1ad9h1b0ah1b2fh1fb3h1d0ch1d2eh1d3fh1dfeh1dffh1e1dh1fe8h1ff5h21a6h2216hbe9i1155h) From: Chen Guangyu-B42378 To: Timur Tabi CC: "shawn.guo@linaro.org" , "broonie@kernel.org" , "linux-arm-kernel@lists.infradead.org" , "devicetree@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "dmaengine@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "alsa-devel@alsa-project.org" , "rob.herring@calxeda.com" , "mark.rutland@arm.com" , "swarren@wwwdotorg.org" , "pawel.moll@arm.com" , "ijc+devicetree@hellion.org.uk" , "s.hauer@pengutronix.de" , Huang Shijie-B32955 Subject: Re: [PATCH 2/3] ASoC: fsl_ssi: Add dual fifo mode support Thread-Topic: [PATCH 2/3] ASoC: fsl_ssi: Add dual fifo mode support Thread-Index: AQHO1KNwOHeCmTMBykCDurVsO/abRZoLn2+AgAADDB0= Date: Tue, 29 Oct 2013 12:53:35 +0000 Message-ID: References: <02f8867363ed3038a0a70703856e4b642fef4339.1383047327.git.b42378@freescale.com>,<526FAD41.2000805@tabi.org> In-Reply-To: <526FAD41.2000805@tabi.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT MIME-Version: 1.0 X-OriginatorOrg: freescale.com X-FOPE-CONNECTOR: Id%0$Dn%*$RO%0$TLS%0$FQDN%$TlsDn% Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1019 Lines: 25 Without dual fifo support, handware underrun would occasionally occur and then two audio channels would physically swap. This could be easily reproduced in low bus frequency situation, while it would be better if we enable dual fifo. Sent by Android device. Timur Tabi wrote: Nicolin Chen wrote: > By enabling dual fifo mode, it would allow SSI enter a better performance > to transimit/receive data without occasional hardware underrun/overrun. Have you measured any real performance gain with this patch? I considered adding dual-FIFO support when I originally wrote this driver, but it didn't appear to have any real benefit, but it used twice as many DMA channels. I'm concerned that this is another patch that just enables a useless feature. -- 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/