From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751642AbXDNQ7y (ORCPT ); Sat, 14 Apr 2007 12:59:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751627AbXDNQ7y (ORCPT ); Sat, 14 Apr 2007 12:59:54 -0400 Received: from mx1.redhat.com ([66.187.233.31]:44153 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751642AbXDNQ7x (ORCPT ); Sat, 14 Apr 2007 12:59:53 -0400 Date: Sat, 14 Apr 2007 09:58:52 -0700 From: Pete Zaitcev To: jeremy@jeremya.com Cc: linux-kernel@vger.kernel.org, zaitcev@redhat.com Subject: Re: [PATCH] usb bulk transfer: 1024 byte packets Message-Id: <20070414095852.c5e3911a.zaitcev@redhat.com> In-Reply-To: <9457.24.247.238.75.1176556465.squirrel@secure.gandhilinux.org> References: <200704131256.47570.jeremy@jeremya.com> <20070413191654.1abdbafc.zaitcev@redhat.com> <9457.24.247.238.75.1176556465.squirrel@secure.gandhilinux.org> Organization: Red Hat, Inc. X-Mailer: Sylpheed 2.3.1 (GTK+ 2.10.11; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 14 Apr 2007 09:14:25 -0400 (EDT), "Jeremy C. Andrus" wrote: > On Fri, April 13, 2007 22:16, Pete Zaitcev wrote: > > The transfer size in the URB is not limited by the maximum packet > > size. The HC driver splits up the transfer as specified by URB into > > the required number of packets. > > The problem was not in the transfer from PC -> Device, but from Device > -> PC. If I remember correctly, the 512 limit (in the > urb->transfer_flags) is used to setup the DMA. When the device sent > packets which were 1024 bytes in size, the urb came back with a status > set to -EOVERFLOW. It's a bug in your driver. Supply the correct size with the URB and all will be fine. Like I said, HC splits up the transfer transparently, no matter what direction. -- Pete