From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clemens Ladisch Subject: Re: [PATCH] ALSA ymfpci - Add "Playback" to FM Legacy Volume control Date: Mon, 12 Sep 2011 16:02:05 +0200 Message-ID: <4E6E10DD.2060508@ladisch.de> References: <4E6CD899.2090000@ladisch.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from out4.smtp.messagingengine.com (out4.smtp.messagingengine.com [66.111.4.28]) by alsa0.perex.cz (Postfix) with ESMTP id AF881103874 for ; Mon, 12 Sep 2011 16:01:46 +0200 (CEST) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Raymond Yau Cc: ALSA Development Mailing List List-Id: alsa-devel@alsa-project.org Raymond Yau wrote: > How accurate is the ymfpci timer ? The period interrupts are not accurate at all. The ymfpci hardware internally uses fixed periods of 256 frames at 48 kHz; the driver reports a period interrupt when the next hardware interrupt at or after a period boundary occurs. The current position reported by the hardware is the position at the time of the last hardware interrupt. > my ymf724f seem play quite well with alsa "hw" device but with bad > noise with alsa-pulse plugin (e.g. aplay when not using default period > times ) and it also occurrs on benshee on ubuntu 11.4 live cd It should be possible to increase accuracy by using the hardware period parameters (48 kHz _and_ 256 frames/period). TODO: implement support for the NORESAMPLE flag. Regards, Clemens