Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757443Ab0HaOEv (ORCPT ); Tue, 31 Aug 2010 10:04:51 -0400 Received: from mail-yx0-f174.google.com ([209.85.213.174]:46758 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757306Ab0HaOEt convert rfc822-to-8bit (ORCPT ); Tue, 31 Aug 2010 10:04:49 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=k6lrcfjcgc2SLfi8f3UuJgPXQcNhkpr6wDrM+jwg5OzZf8WunONPZBKGL9EmFU+Ifx hYmdKzSbPQVMLEo30gis3x+b8YFZVgOUz0+7VjNt31Hobx6g92lIAjIcxtfmlqfc6TPj WxL5BdMTwNVFHZshSJg70HsirJAcrc8J8lYts= MIME-Version: 1.0 In-Reply-To: References: <4C7CA411.5070601@ladisch.de> Date: Tue, 31 Aug 2010 22:04:47 +0800 Message-ID: Subject: Re: [PATCH] USB: output an error message when the pipe type doesn't match the endpoint type From: Xiaofan Chen To: Alan Stern Cc: Clemens Ladisch , Simon Arlott , Greg KH , Linux Kernel Mailing List , USB list Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1291 Lines: 36 On Tue, Aug 31, 2010 at 9:52 PM, Alan Stern wrote: > On Tue, 31 Aug 2010, Clemens Ladisch wrote: > >> Simon Arlott wrote: >> > Commit f661c6f8c67bd55e93348f160d590ff9edf08904 adds a check of the pipe type if >> > CONFIG_USB_DEBUG is enabled, >> >> I didn't see that commit last year, but wouldn't it break devices like >> the ESI MIDI Mate whose descriptors want to have low-speed bulk transfers >> and where the driver has to submit interrupt transfers instead to get it >> to work at all? > > When the kernel sees those invalid low-speed bulk endpoint descriptors, > it changes its internal copy of the descriptor to interrupt. ?Hence > when the driver submits interrupt URBs, they work correctly. > Interesting. FYI: even though XP/Win2k allow low-speed bulk endpoints, Vista and Win7 do not allow that. There are hacks to get around that. http://www.recursion.jp/avrcdc/lowbulk.html I took a look at the libusb-win32 source and indeed the author is using the same trick of submit interrupt URBs. -- Xiaofan -- 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/