From owner-freebsd-multimedia@FreeBSD.ORG Mon Mar 7 03:53:59 2005 Return-Path: Delivered-To: freebsd-multimedia@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E5EC216A4CE for ; Mon, 7 Mar 2005 03:53:59 +0000 (GMT) Received: from ns.kt-is.co.kr (ns.kt-is.co.kr [211.218.149.125]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5CAFE43D1F for ; Mon, 7 Mar 2005 03:53:59 +0000 (GMT) (envelope-from yongari@kt-is.co.kr) Received: from michelle.kt-is.co.kr (ns2.kt-is.co.kr [220.76.118.193]) (authenticated bits=128) by ns.kt-is.co.kr (8.12.10/8.12.10) with ESMTP id j273o9Ah005166 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL); Mon, 7 Mar 2005 12:50:09 +0900 (KST) Received: from michelle.kt-is.co.kr (localhost.kt-is.co.kr [127.0.0.1]) by michelle.kt-is.co.kr (8.13.1/8.13.1) with ESMTP id j273rqk4001273 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 7 Mar 2005 12:53:52 +0900 (KST) (envelope-from yongari@kt-is.co.kr) Received: (from yongari@localhost) by michelle.kt-is.co.kr (8.13.1/8.13.1/Submit) id j273rp1T001272; Mon, 7 Mar 2005 12:53:51 +0900 (KST) (envelope-from yongari@kt-is.co.kr) Date: Mon, 7 Mar 2005 12:53:51 +0900 From: Pyun YongHyeon To: Mathew Kanner Message-ID: <20050307035351.GD951@kt-is.co.kr> References: <20050305224005.GC4237@cnd.mcgill.ca> <20050306162811.694d9c82@Magellan.Leidinger.net> <20050307025927.GB951@kt-is.co.kr> <20050307032823.GH4237@cnd.mcgill.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050307032823.GH4237@cnd.mcgill.ca> User-Agent: Mutt/1.4.2.1i X-Filter-Version: 1.11a (ns.kt-is.co.kr) cc: freebsd-multimedia@freebsd.org cc: Alexander Leidinger Subject: Re: uaudio patch, configurable buffer size X-BeenThere: freebsd-multimedia@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: yongari@kt-is.co.kr List-Id: Multimedia discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Mar 2005 03:54:00 -0000 On Sun, Mar 06, 2005 at 10:28:23PM -0500, Mathew Kanner wrote: [...] > Per your other e-mail, as present in the source, is having the > default size of 16*1024 and doing bus_dma_tag_create with a maxsegz of > 0x3fff (16*1024-1) a bug? I think so. I couldn't verify it since I don't have real hardware and don't know USB audio internals. But I believe almost all audio hardwares can transfer upto 64KB in a single DMA request. Many device drivers for PCI audio cards use 0x3ffff(256KB - 1). I don't know those hardwares can transfer upto that huge size and hardly believe this. But pcm(4) further restricts the buffer size to 64KB in pcm_getbuffersize and we created DMA tag with single segment, so it would be OK to use 0x3ffff. -- Regards, Pyun YongHyeon http://www.kr.freebsd.org/~yongari | yongari@freebsd.org