From owner-freebsd-usb@FreeBSD.ORG Fri Sep 18 03:09:23 2009 Return-Path: Delivered-To: freebsd-usb@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EDF2A106566B for ; Fri, 18 Sep 2009 03:09:23 +0000 (UTC) (envelope-from tlb@tlb.org) Received: from anybots.com (mail.anybots.com [64.142.12.96]) by mx1.freebsd.org (Postfix) with SMTP id B33DB8FC1A for ; Fri, 18 Sep 2009 03:09:23 +0000 (UTC) Received: (qmail 42578 invoked from network); 18 Sep 2009 03:09:23 -0000 Received: from unknown (HELO ?10.10.10.66?) (10.10.10.66) by 10.10.10.20 with SMTP; 18 Sep 2009 03:09:23 -0000 Message-Id: From: Trevor Blackwell To: freebsd-usb@freebsd.org Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v935.3) Date: Thu, 17 Sep 2009 20:09:22 -0700 X-Mailer: Apple Mail (2.935.3) Subject: Transfer size limits X-BeenThere: freebsd-usb@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: FreeBSD support for USB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Sep 2009 03:09:24 -0000 What's the largest practical bulk transfer size in the -8 USB stack? I'm currently transferring frames through a UE_BULK pipe from a Mightex camera (it uses bulk, not isochronous.) Currently, I'm setting usbd_xfer_max_len(xfer)==32768. If I could set it large enough for a complete frame (5 MB), it would simplify the logic of my driver. Large transfers didn't work reliably with the -7 USB stack, because of some obscure problem with setting up DMA transfers in the ehci driver with more than a few separate physical regions. -- Trevor Blackwell 650 776 7870 tlb@tlb.org