From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7285 invoked by alias); 14 Apr 2005 08:24:35 -0000 Mailing-List: contact ecos-discuss-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@ecos.sourceware.org Received: (qmail 6686 invoked from network); 14 Apr 2005 08:24:25 -0000 Received: from unknown (HELO mail.jenoptik.com) (217.17.196.194) by sourceware.org with SMTP; 14 Apr 2005 08:24:25 -0000 Received: from JO-EX01.JENOPTIK.NET ([10.250.1.4]) by mail.jenoptik.com (8.13.3/8.13.1) with ESMTP id j3E8OKZf016631; Thu, 14 Apr 2005 10:24:22 +0200 content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Date: Thu, 14 Apr 2005 08:24:00 -0000 Message-ID: <5A8A17126B73AC4C83968F6C4505E3C501F32822@JO-EX01.JENOPTIK.NET> X-MS-Has-Attach: X-MS-TNEF-Correlator: From: "Fuchs, Torsten" To: "Frank Pagliughi" , Subject: AW: [ECOS] Splitting USB-Packets X-SW-Source: 2005-04/txt/msg00155.txt.bz2 Hi, I'm using a philips ISP1583 with a self-written driver in a digital camera = to implement the PTP (Picture transfer protocol). So there are only bulk an= d some interrupt transfers. The hardware does not send the zero packet auto= matically. Modifying the device driver is not the problem but getting a fla= g through the overlying slave package, that I want to use. It seems I have = to modify it and be no more compatible to the original package. I just wond= ered if no-one had the problem of splitting larger packets into pieces unti= l now.=20 The PTP-Standard says that the first short or zero packet ends the transfer= , so I think there is no other way than modifying the driver. The host side is a PC or MAC. I did not know that WinXP breaks up the packe= ts in smaller units when they exceed a certain size. But relying on this "f= eature" is not a safe way for the device. Torsten Fuchs -----Urspr=FCngliche Nachricht----- Von: Frank Pagliughi [mailto:fpagliughi@mindspring.com] Gesendet: Mittwoch, 13. April 2005 23:41 An: Fuchs, Torsten; ecos-discuss@sources.redhat.com Betreff: RE: [ECOS] Splitting USB-Packets Which USBS device/driver are you using? Does the hardware automatically send the zero packet? I assume not, so you could modify the driver for your specific application - if that's what you really want to do. I've been working with Philips chips, where you have to send the zero packet explicitly. And you do *need* to do this by default, especially if you're using the higher level File I/O functions. BTW, are you talking about Bulk transfers? And what are you using on the host side? I don't know that low-level USB functions guarantee undivided packets back to user mode code (or even upper level drivers). In a Windows XP device driver I just wrote I would see Bulk IN packets broken up by the underlying bus driver when they were around the 4kB page size. That would require repeated read() calls by the application to reconstruct the full packet, sort of like reading a TCP stream. Frank Pagliughi -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss