From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: Scatter Gather DMA Date: Wed, 05 Mar 2003 17:51:50 +0100 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: References: <200303051209.AA33751384@embedded.cl> Mime-Version: 1.0 (generated by SEMI 1.14.4 - "Hosorogi") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: <200303051209.AA33751384@embedded.cl> Errors-To: alsa-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: mjander@embedded.cl Cc: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org At Wed, 5 Mar 2003 12:09:21 -0400, mjander wrote: > > Hi, > > Another question... :) > > The Aureal Vortex has Scatter Gather DMA's for each audio channel. > But these SG DMA > support only max 4 pages. Each page can have a programable size of > upto 4 KB. > I was studying the ALSA SG scheme and it doesnt seme to fit into > the aureal vortex > SG buffer scheme, because ALSA, as far as i understood, only > allows pages of the kernel PAGE_SIZE size, and allocates as many > pages (without cound limit ?) until the buffer size is reached. then you can define max_buffer_bytes as 4 * 4096. then sg-allocator will allocate up to 4 pages. > But the PAGE_SIZE around 0x400 or 0x800, which is rather small. sorry, what are these numbers? > On the Aureal vortex soundcard side i have 4 registers for page > base address, and some sort of config regs to configure each page > size and the next page for each page. I just dont understand how > could i plug this two apparently incompatible things together. Takashi ------------------------------------------------------- This SF.net email is sponsored by: Etnus, makers of TotalView, The debugger for complex code. Debugging C/C++ programs can leave you feeling lost and disoriented. TotalView can help you find your way. Available on major UNIX and Linux platforms. Try it free. www.etnus.com