From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: full/half duplex support Date: Thu, 18 Nov 2004 14:17:32 +0100 Message-ID: References: Mime-Version: 1.0 (generated by SEMI 1.14.5 - "Awara-Onsen") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: Sender: alsa-devel-admin@lists.sourceforge.net Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Luuk van Dijk Cc: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org At Mon, 15 Nov 2004 17:03:21 +0100, Luuk van Dijk wrote: > > LS. > > I am currently writing a driver for the ADI 1836 on the (ongoing) > blackfin/uclinux port (blackfin.uclinux.org) and I have some questions (that > I'll post in separate mails, so that they may be separate threads) > > The particular hardware configuration I am programming for is full-duplex in > principle, i.e. it should be no problem to send and receive pcm bitstreams > simultaneously, except that it requires that both dma channels are started > simultaneously. Currently, I configure an unused substream with a dummy dma > buffer, but the alsa mid layer seems to handle this badly: it appears to > re-triggers the last-started substream when it finds out that the dma is at > an other address than it expects. Sorry, the situation is not clear for me. Do you mean substream as the ALSA term? So, you have two or more substreams assigned to a single PCM device, and the DMAs are free-running when the substreams are unused? Takashi ------------------------------------------------------- This SF.Net email is sponsored by: InterSystems CACHE FREE OODBMS DOWNLOAD - A multidimensional database that combines robust object and relational technologies, making it a perfect match for Java, C++,COM, XML, ODBC and JDBC. www.intersystems.com/match8