From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758683AbcIHI6d (ORCPT ); Thu, 8 Sep 2016 04:58:33 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:54650 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758628AbcIHI62 (ORCPT ); Thu, 8 Sep 2016 04:58:28 -0400 Date: Thu, 8 Sep 2016 10:58:19 +0200 From: Greg KH To: Lu Baolu Cc: Mathias Nyman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2 1/1] usb: xhci: fix return value of xhci_setup_device() Message-ID: <20160908085819.GA21294@kroah.com> References: <1473295302-3956-1-git-send-email-baolu.lu@linux.intel.com> <20160908063828.GA5485@kroah.com> <57D11355.8040505@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57D11355.8040505@linux.intel.com> User-Agent: Mutt/1.7.0 (2016-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 08, 2016 at 03:29:25PM +0800, Lu Baolu wrote: > Hi Greg, > > On 09/08/2016 02:38 PM, Greg KH wrote: > > On Thu, Sep 08, 2016 at 08:41:02AM +0800, Lu Baolu wrote: > >> xhci_setup_device() should return failure with correct error number > >> when xhci host has died, removed or halted. > >> > >> Cc: stable@vger.kernel.org # 4.3+ > > Why is this a stable kernel issue? What bug does it fix that affects > > users? > > During usb device enumeration, if xhci host is not accessible (died, > removed or halted), the hc_driver->address_device() should return > a corresponding error code to usb core. But current xhci driver just > returns success. This will mislead usb core to continue enumeration: > reading device descriptor, which will result in failure, and users will > get a misleading message like "device descriptor read/8, error -110". Why didn't you include this in the changelog text so that it is obvious why this patch is needed? Don't just describe what the patch does, we can read C code, describe _why_ it is needed. thanks, greg k-h