From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Clemens Ladisch" Subject: Re: [PATCH] US-122L Driver, v0 Date: Thu, 08 Nov 2007 17:14:51 +0100 Message-ID: <1194538491.3947.1220263479@webmail.messagingengine.com> References: <200711071641.28551.fzu@wemgehoertderstaat.de> <200711071955.16686.fzu@wemgehoertderstaat.de> <1194506689.14959.1220188671@webmail.messagingengine.com> <200711081337.05417.fzu@wemgehoertderstaat.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from out1.smtp.messagingengine.com (out1.smtp.messagingengine.com [66.111.4.25]) by alsa0.perex.cz (Postfix) with ESMTP id BA907248EA for ; Thu, 8 Nov 2007 17:14:57 +0100 (CET) Content-Disposition: inline In-Reply-To: <200711081337.05417.fzu@wemgehoertderstaat.de> 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: Karsten Wiese Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org Karsten Wiese wrote: > snd-usb-audio uses number_of_packets equalling multiples of 8 currently > when transfering over USB 2.0, no? > If so, with above patch that "multiples of 8"-thing could go away and > snd-usb-audio could achieve up to 8 times less userspace-activation-jitter > in low latency setups like 128 frames/period, 2 periods. I'm using the 8-microframes alignment because ehci-hcd configures the controller to interrupt at most every 1 ms. It has a module option to change this, but as long as snd-usb-audio cannot detect a lower setting, it would not make sense to allow shorter periods. Regards, Clemens