From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752392AbbJ2Mvr (ORCPT ); Thu, 29 Oct 2015 08:51:47 -0400 Received: from mail-lb0-f169.google.com ([209.85.217.169]:35693 "EHLO mail-lb0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750753AbbJ2Mvp (ORCPT ); Thu, 29 Oct 2015 08:51:45 -0400 Subject: Re: [PATCH v2 1/1] usb: xhci: fix checking ep busy for CFC To: Lu Baolu , Mathias Nyman , Greg Kroah-Hartman References: <1446086797-7218-1-git-send-email-baolu.lu@linux.intel.com> Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org From: Sergei Shtylyov Message-ID: <5632165E.2020102@cogentembedded.com> Date: Thu, 29 Oct 2015 15:51:42 +0300 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <1446086797-7218-1-git-send-email-baolu.lu@linux.intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. On 10/29/2015 5:46 AM, Lu Baolu wrote: > Function ep_ring_is_processing() checks the dequeue pointer > in endpoint context to know whether an endpoint is busy with > processing TRBs. This is not correct since dequeue pointer > field in an endpoint context is only valid when the endpoint > is in Halted or Stopped states. This buggy code causes audio > noise when playing sound with USB headset connected to host > controllers which support CFC (one of xhci 1.1 features). > > This patch should exist in stable kernel since v4.3. > > Reported-and-tested-by: YD Tseng > Signed-off-by: Lu Baolu > > --- > v1->v2: > Implement the logic in xhci_queue_isoc_tx_prepare() instead of > a seperated function as suggested by Mathias. > > --- > drivers/usb/host/xhci-ring.c | 32 ++++++-------------------------- > 1 file changed, 6 insertions(+), 26 deletions(-) > > diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c > index fa83625..8edc286 100644 > --- a/drivers/usb/host/xhci-ring.c > +++ b/drivers/usb/host/xhci-ring.c [...] > @@ -3983,10 +3961,12 @@ int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci, gfp_t mem_flags, > } > > /* Calculate the start frame and put it in urb->start_frame. */ > - if (HCC_CFC(xhci->hcc_params) && > - ep_ring_is_processing(xhci, slot_id, ep_index)) { > - urb->start_frame = xep->next_frame_id; > - goto skip_start_over; > + if (HCC_CFC(xhci->hcc_params)) { > + if ((le32_to_cpu(ep_ctx->ep_info) & EP_STATE_MASK) > + == EP_STATE_RUNNING && > + !list_empty(&ep_ring->td_list)) > + urb->start_frame = xep->next_frame_id; > + goto skip_start_over; Forgot {}? > } > > start_frame = readl(&xhci->run_regs->microframe_index); MBR, Sergei