From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Lee Subject: Re: USB asynchronous mode feedback format Date: Fri, 15 Oct 2010 21:31:50 +0800 Message-ID: <1287149510.2344.8.camel@desktop-alex> References: <1287046026.4cb6c38a2a179@discus.singnet.com.sg> <201010151408.30428.julian@jusst.de> <1287147135.3429.1.camel@laptop-alex> <201010151504.56742.julian@jusst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp42.singnet.com.sg (smtp42.singnet.com.sg [165.21.103.146]) by alsa0.perex.cz (Postfix) with ESMTP id 734A1103811 for ; Fri, 15 Oct 2010 15:31:54 +0200 (CEST) In-Reply-To: <201010151504.56742.julian@jusst.de> 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: Julian Scheel Cc: alsa-devel@alsa-project.org, Daniel Mack List-Id: alsa-devel@alsa-project.org On Fri, 2010-10-15 at 15:04 +0200, Julian Scheel wrote: > Ah right, thanks. > Well now I swapped data[1] and data[2]. When monitoring the amount of data I > get per read, it is constant at 192bytes, which would be expected for feedback > ratio of 48, right? But if I have 0x06 to 0x07 for example I do still get > exactly 192bytes per read, shouldn't I get less data in that case? (I always > try to read up to MAXPACKETSIZE which is 512, btw) Suggest: (1) The feedback rate has to fall withing +/- 10% of the nominal rate. Otherwise it is ignored. (2) You need to find out exactly how many samples the host sends you. Look at my sdr-widget code, for example. Then you read what the host sends you. (3) Do a > dmesg | tail after unplugging and plugging your USB device in. Then you can see whether there are any errors in your syncpipe btw, what is your Linux kernel version? Alex