Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758163AbYADBVu (ORCPT ); Thu, 3 Jan 2008 20:21:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757176AbYADBT5 (ORCPT ); Thu, 3 Jan 2008 20:19:57 -0500 Received: from nwd2mail11.analog.com ([137.71.25.57]:55543 "EHLO nwd2mail11.analog.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756284AbYADBTt convert rfc822-to-8bit (ORCPT ); Thu, 3 Jan 2008 20:19:49 -0500 X-IronPort-AV: E=Sophos;i="4.24,241,1196658000"; d="scan'208";a="46169481" From: Robin Getz Organization: Blackfin uClinux org To: "Richard D" Subject: Re: [linux-usb-devel] [PATCH] : Allow embedded developers USB options normally reserved for OTG Date: Thu, 3 Jan 2008 20:20:47 -0500 User-Agent: KMail/1.9.5 Cc: "Bryan Wu" , "David Brownell" , linux-usb-devel@lists.sourceforge.net, gregkh@suse.de, linux-kernel@vger.kernel.org References: <200801020948.51310.rgetz@blackfin.uclinux.org> <386072610801030005g7408f333m935c665c82d3412a@mail.gmail.com> <001c01c84e2a$ad3bceb0$07b36c10$@com> In-Reply-To: <001c01c84e2a$ad3bceb0$07b36c10$@com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200801032020.47642.rgetz@blackfin.uclinux.org> X-OriginalArrivalTime: 04 Jan 2008 01:19:47.0682 (UTC) FILETIME=[E5624C20:01C84E6F] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1463 Lines: 38 On Thu 3 Jan 2008 12:04, Richard D pondered: > Does all USB Host controller hardware have the ability to disable PING? I think they do. (or at least should)... http://www.intel.com/technology/usb/download/ehci-r10.pdf ================== 4.11 Ping Control (page 88) USB 2.0 defines an addition to the protocol for high-speed devices called Ping. Ping is required for all USB 2.0 High-speed bulk and control endpoints. Ping is not allowed for a split-transaction stream. This extension to the protocol eliminates the bad side-effects of Naking OUT endpoints. The Status field has a Ping State bit, which the host controller uses to determine the next actual PID it will use in the next transaction to the endpoint (see Table 3-16). Table 4–12 illustrates the state transition table for the host controller's responsibility for maintaining the PING protocol. Refer to Chapter 8 in the USB Specification Revision 2.0 for detailed description on the Ping protocol. =============== I think the musb is just missing the PING/OUT State table, as described in table 4-12. I think this is controlled in the ehci driver with: host/ehci.h:#define QTD_STS_PING (1 << 0) /* issue PING? */ -Robin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/