From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83637C433E0 for ; Thu, 9 Jul 2020 16:47:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4C9EB207DD for ; Thu, 9 Jul 2020 16:47:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728299AbgGIQrT convert rfc822-to-8bit (ORCPT ); Thu, 9 Jul 2020 12:47:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:40566 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728037AbgGIQrT (ORCPT ); Thu, 9 Jul 2020 12:47:19 -0400 From: bugzilla-daemon@bugzilla.kernel.org To: linux-usb@vger.kernel.org Subject: [Bug 208357] snd-usb-audio broken for 06f8:b000 since 4.9.189 Date: Thu, 09 Jul 2020 16:47:19 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo drivers_usb@kernel-bugs.kernel.org X-Bugzilla-Product: Drivers X-Bugzilla-Component: USB X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: blocking X-Bugzilla-Who: stern@rowland.harvard.edu X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: drivers_usb@kernel-bugs.kernel.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=208357 --- Comment #4 from Alan Stern (stern@rowland.harvard.edu) --- Well, the problem is clear enough: Interface 5 uses endpoint 1-OUT in alternate setting 1, 1-IN in alternate setting 2, and both 1-OUT and 1-IN in alternate setting 3. At the same time, interface 7 alternate setting 1 uses endpoint 1-OUT and interface 8 alternate setting 1 uses endpoint 1-IN. According to the USB spec, different interfaces are not allowed to use the same endpoints. (The exact statement, in section 9.6.3 of the USB-2.0 specification, is: "An endpoint is not shared among interfaces within a single configuration unless the endpoint is used by alternate settings of the same interface." IMO the word "unless" should have been "except when".) This device would never pass the USB validation suite and would not be allowed to use the USB logo. Under the circumstances, it looks like interface 5 is not intended for general use, since it is described as Vendor-Specific. Does it get used in your system? The answer can be found in the /sys/kernel/debug/usb/devices file (with the device plugged in under an earlier kernel where it works okay). It may turn out that the way to deal with this problem is to add ENDPOINT_IGNORE quirks for interface 5 on this device. -- You are receiving this mail because: You are watching the assignee of the bug.