From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: Scatter Gather Date: Tue, 02 Mar 2004 11:23:04 +0100 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: References: <1078200582.1446.21.camel@localhost> Mime-Version: 1.0 (generated by SEMI 1.14.5 - "Awara-Onsen") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Giuliano Pochini Cc: Manuel Jander , Alsa Devel list List-Id: alsa-devel@alsa-project.org At Tue, 02 Mar 2004 11:16:33 +0100 (CET), Giuliano Pochini wrote: > > > On 02-Mar-2004 Manuel Jander wrote: > > >> Yes. Every driver using SG must do this. Look into bt87x.c or > >> via82xx.c for examples. > > > > Well, i guess in that case the period size loses any relevance in > > terms of efficiency. > > Efficiency about what ? If the hardware can be programmed to use > any period size, then the application is free to choose the size > it prefers. It's not a bad thing. NB: the interrupt should be > generated at the end of the period, not at the end of each block, > eg. when it crosses the page boundary. well, it's ok to generate irqs at each page boundary, too, as long as the driver processes it properly, i.e. calling snd_pcm_period_elapsed() only at the irq of the end of period. of course, less irqs are better from the performance viewpoint. Takashi ------------------------------------------------------- SF.Net is sponsored by: Speed Start Your Linux Apps Now. Build and deploy apps & Web services for Linux with a free DVD software kit from IBM. Click Now! http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click