From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <5501A376.3000700@linux.intel.com> Date: Thu, 12 Mar 2015 16:32:22 +0200 From: Mathias Nyman MIME-Version: 1.0 To: Lu Baolu , Mathias Nyman , Greg Kroah-Hartman CC: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable Subject: Re: [PATCH 1/1] usb: xhci: handle Config Error Change (CEC) in xhci driver References: <1425629552-17808-1-git-send-email-baolu.lu@linux.intel.com> In-Reply-To: <1425629552-17808-1-git-send-email-baolu.lu@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: On 06.03.2015 10:12, Lu Baolu wrote: > Linux xHCI driver doesn't report and handle port cofig error change. > If Port Configure Error for root hub port occurs, CEC bit in PORTSC > would be set by xHC and remains 1. This happends when the root port > fails to configure its link partner, e.g. the port fails to exchange > port capabilities information using Port Capability LMPs. > > Then the Port Status Change Events will be blocked until all status > change bits(CEC is one of the change bits) are cleared('0') (refer to > xHCI spec 4.19.2). Otherwise, the port status change event for this > root port will not be generated anymore, then root port would look > like dead for user and can't be recovered until a Host Controller > Reset(HCRST). > > This patch is to check CEC bit in PORTSC in xhci_get_port_status() > and set a Config Error in the return status if CEC is set. This will > cause a ClearPortFeature request, where CEC bit is cleared in > xhci_clear_port_change_bit(). > > [Mathias Nyman contributed the idea. The commit log is based on patch > posted at http://marc.info/?l=linux-kernel&m=142323612321434&w=2] > > Signed-off-by: Lu Baolu > Cc: stable # v3.2+ Looks good, I'll add it to the queue, -Mathias