From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Davis Subject: Re: AW: general audio card Q Date: Wed, 31 Jul 2002 08:47:29 -0400 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <200207311245.OAA19422@alsa.alsa-project.org> References: Return-path: Received: from newmx2.fast.net (newmx2.fast.net [209.92.1.32]) by alsa.alsa-project.org (8.9.3/8.9.3/SuSE Linux 8.9.3-0.1) with ESMTP id OAA19422 for ; Wed, 31 Jul 2002 14:45:52 +0200 In-Reply-To: Your message of "Wed, 31 Jul 2002 13:20:24 +0200." Errors-To: alsa-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: Karsten Wiese Cc: alsa-devel@alsa-project.org, l5gibson@hotmail.com List-Id: alsa-devel@alsa-project.org >Paul wrote: > >> cards that do not use DMA should generally be considered inferior >> because of the extra CPU cycles they force on the host system. > >not generally. i.e. the pinnacle/fiji way is to map a piece of memory into >the pc's memory space. >thus an application using alsa-mmap can write (or read) directly into the >cards pcm-memory. >pretty efficiently, don't you think? (except that its ISA-memory) >(it can do so with 2 or 3 periods per buffer). >I don't see any drawback here caused by the lack of DMA. yes, but this isn't what I mean by "a card that doesn't use DMA". cards that don't use DMA require the host CPU to issue an instruction per-small-piece-of-data to move it from host memory to the interface memory. what you're describing is still instruction-free movement of data between the two. the fact that the mapping is interface->host rather than host->interface (as on the rme9652, sblive, ice1712 and others) doesn't change that all that much. --p ------------------------------------------------------- This sf.net email is sponsored by: Dice - The leading online job board for high-tech professionals. Search and apply for tech jobs today! http://seeker.dice.com/seeker.epl?rel_code=31