From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Courtier-Dutton Subject: DMA feature question. Date: Sat, 26 Jun 2004 15:44:32 +0100 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <40DD8BD0.40705@superbug.demon.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from anchor-post-37.mail.demon.net (anchor-post-36.mail.demon.net [194.217.242.86]) by alsa.alsa-project.org (ALSA's E-mail Delivery System) with ESMTP id 7859B2CD for ; Sat, 26 Jun 2004 15:42:02 +0200 (MEST) Received: from superbug.demon.co.uk ([80.176.146.252] helo=[192.168.1.10]) by anchor-post-37.mail.demon.net with esmtp (Exim 3.35 #1) id 1BeDRR-000HLc-0b for alsa-devel@alsa-project.org; Sat, 26 Jun 2004 14:42:01 +0100 Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: ALSA development List-Id: alsa-devel@alsa-project.org I have a sound card that requires access to 2 DMA areas per substream. 1) Is for the audio samples buffer. I can already do that with: err = snd_pcm_lib_preallocate_pages(substream, SNDRV_DMA_TYPE_DEV, snd_dma_pci_data(emu->pci), 32*1024, 32*1024); 2) Is for a table of periods.. This table will contain:- { u32 Pointer_into_samples_buffer, u32 number_of_bytes } So, each record in the table is 8 bytes long, and identify each period in the buffer. So, the table will contain a list of the different periods. So, if there are 8 periods, the table will have 8 entries, each 8 bytes long, so I will need a DMA map for 64 bytes. Is there any way to use the snd_pcm_lib_preallocate_pages() for this "table or periods". If not, I will just have to make (1) a bit bigger, and place the "table of periods" in there. Cheers James ------------------------------------------------------- This SF.Net email sponsored by Black Hat Briefings & Training. Attend Black Hat Briefings & Training, Las Vegas July 24-29 - digital self defense, top technical experts, no vendor pitches, unmatched networking opportunities. Visit www.blackhat.com