From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Nikula Subject: Re: [RFC 3/4] OMAP3: McBSP: Add interface for transmit FIFO state query Date: Tue, 2 Mar 2010 16:06:15 +0200 Message-ID: <20100302160615.51cfbd64.jhnikula@gmail.com> References: <1267537191-25254-1-git-send-email-peter.ujfalusi@nokia.com> <1267537191-25254-4-git-send-email-peter.ujfalusi@nokia.com> <1267537920.24345.7.camel@eenurkka-desktop> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from ey-out-1920.google.com (ey-out-1920.google.com [74.125.78.148]) by alsa0.perex.cz (Postfix) with ESMTP id 954951038E8 for ; Tue, 2 Mar 2010 15:05:27 +0100 (CET) Received: by ey-out-1920.google.com with SMTP id 26so73723eyw.16 for ; Tue, 02 Mar 2010 06:05:27 -0800 (PST) In-Reply-To: <1267537920.24345.7.camel@eenurkka-desktop> 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: ext-eero.nurkkala@nokia.com Cc: "tiwai@suse.de" , "alsa-devel@alsa-project.org" , "broonie@opensource.wolfsonmicro.com" , "Ujfalusi Peter (Nokia-D/Tampere)" , "lrg@slimlogic.co.uk" List-Id: alsa-devel@alsa-project.org On Tue, 02 Mar 2010 15:52:00 +0200 Eero Nurkkala wrote: > Reading the XBUFFSTAT register is by no means accurate. > IIRC, it reports the buffer status incorrectly about 1/50 times > on average (@ 48000khz); with simple math, it may be read during the DMA > burst. Or is it guaranteed not being read during DMA transfer / have > you otherwise verified the behavior? > Do you remember how big was this variation? Was it near the burst size or some arbitrary difference? -- Jarkko