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 35A5EC2BA2B for ; Thu, 9 Apr 2020 14:01:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0CFF72145D for ; Thu, 9 Apr 2020 14:01:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727125AbgDIOBm convert rfc822-to-8bit (ORCPT ); Thu, 9 Apr 2020 10:01:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:33228 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726992AbgDIOBl (ORCPT ); Thu, 9 Apr 2020 10:01:41 -0400 From: bugzilla-daemon@bugzilla.kernel.org To: linux-usb@vger.kernel.org Subject: [Bug 207065] C-media USB audio device stops working from 5.2.0-rc3 onwards Date: Thu, 09 Apr 2020 14:01:41 +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: normal 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=207065 --- Comment #6 from Alan Stern (stern@rowland.harvard.edu) --- On Thu, 9 Apr 2020 bugzilla-daemon@bugzilla.kernel.org wrote: > --- Comment #4 from Mathias Nyman (mathias.nyman@linux.intel.com) --- > Thanks, traces show its related to Clearing TT buffer after a STALL on > endpoint 0. > > The first stall looks like a protocol stall, not a function stall, meaning > that > endpoint isn't really halted, just that the device does not support the > request in the control transfer. > > Anyway, xhci starts clearing what it assumes is a halted endpoint, > including clearing the hub TT buffer. > > Specs are a bit unclear if TT should be cleared in this case, > or at least I couldn't find it. TTs should be cleared when an error occurs in the protocol. STALL isn't an error; a real error would be a timeout or CRC mismatch or URB cancellation, things like that -- things that might leave the TT in a busy state (because it hasn't sent its final status back to the host) when it ought to be idle. Sending a STALL isn't a protocol error and it does clear the TT status. This is discussed (not as explicitly as one might want) in sections 11.17.3 and 11.17.5 of the USB-2.0 specification. Alan Stern -- You are receiving this mail because: You are watching the assignee of the bug.