From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26112 invoked by alias); 21 Oct 2010 18:32:30 -0000 Received: (qmail 26094 invoked by uid 22791); 21 Oct 2010 18:32:29 -0000 X-SWARE-Spam-Status: No, hits=-1.6 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from hagrid.ecoscentric.com (HELO mail.ecoscentric.com) (212.13.207.197) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 21 Oct 2010 18:32:24 +0000 Received: from localhost (hagrid.ecoscentric.com [127.0.0.1]) by mail.ecoscentric.com (Postfix) with ESMTP id 130082F7800C for ; Thu, 21 Oct 2010 19:32:22 +0100 (BST) Received: from mail.ecoscentric.com ([127.0.0.1]) by localhost (hagrid.ecoscentric.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UwmuZDBcs507; Thu, 21 Oct 2010 19:32:19 +0100 (BST) From: bugzilla-daemon@bugs.ecos.sourceware.org To: ecos-patches@ecos.sourceware.org Subject: [Bug 1001024] STM32 USB driver and proposed USB API change X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: eCos X-Bugzilla-Component: Patches and contributions X-Bugzilla-Keywords: X-Bugzilla-Severity: enhancement X-Bugzilla-Who: chris@zynaptic.com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: low X-Bugzilla-Assigned-To: john@dallaway.org.uk X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: In-Reply-To: References: X-Bugzilla-URL: http://bugs.ecos.sourceware.org/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Date: Thu, 21 Oct 2010 18:32:00 -0000 Message-Id: <20101021183219.837202F78007@mail.ecoscentric.com> Mailing-List: contact ecos-patches-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: ecos-patches-owner@ecos.sourceware.org X-SW-Source: 2010-10/txt/msg00028.txt.bz2 Please do not reply to this email. Use the web interface provided at: http://bugs.ecos.sourceware.org/show_bug.cgi?id=1001024 --- Comment #32 from Chris Holgate 2010-10-21 19:32:15 BST --- (In reply to comment #31) > While I haven't looked through the spec for a while, I believe that you _can_ > have multiple class drivers on a single device without using a virtual hub. I > think it's called a composite device. The descriptor arrangement is a bit more > complicated, but it's still possible. Your recollection of the spec is obviously better than mine. As you say, composite devices are supported and I should probably have used the Google before posting misleading rubbish! However, a single device can still only have one control endpoint and one root descriptor, which means the scenario John mentioned of multiple class drivers calling usbs_start with different (or even the same) control endpoint data structures should never happen. I think that supporting composite drivers is really an issue for a notional USB class driver framework. As far as the existing low level USB slave drivers are concerned, a USB device is just a bundle of endpoints and a bunch of arbitrary descriptors. IMHO that is exactly the right level of abstraction - and any additional support for composite drivers should be added as an extra layer of abstraction between the low level USB slave driver and the class function drivers. -- Configure bugmail: http://bugs.ecos.sourceware.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.