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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 67C06C43219 for ; Thu, 2 May 2019 10:54:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 40E2F20656 for ; Thu, 2 May 2019 10:54:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726489AbfEBKyK (ORCPT ); Thu, 2 May 2019 06:54:10 -0400 Received: from mga02.intel.com ([134.134.136.20]:15382 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726442AbfEBKyJ (ORCPT ); Thu, 2 May 2019 06:54:09 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 May 2019 03:54:08 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,421,1549958400"; d="scan'208";a="154108748" Received: from mattu-haswell.fi.intel.com (HELO [10.237.72.164]) ([10.237.72.164]) by FMSMGA003.fm.intel.com with ESMTP; 02 May 2019 03:54:07 -0700 Subject: Re: [PATCH v3 1/1] usb: xhci: Add Clear_TT_Buffer To: Jim Lin , mathias.nyman@intel.com, gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Alan Stern References: <1556593592-3078-1-git-send-email-jilin@nvidia.com> From: Mathias Nyman Message-ID: Date: Thu, 2 May 2019 13:56:39 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <1556593592-3078-1-git-send-email-jilin@nvidia.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30.4.2019 6.06, Jim Lin wrote: > USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt > processing for full-/low-speed endpoints connected via a TT, the host > software must use the Clear_TT_Buffer request to the TT to ensure > that the buffer is not in the busy state". Good point, xhci isn't making sure TT buffers get cleared when they should. > > In our case, a full-speed speaker (ConferenceCam) is behind a high- > speed hub (ConferenceCam Connect), sometimes once we get STALL on a > request we may continue to get STALL with the folllowing requests, > like Set_Interface. > > Here we add Clear_TT_Buffer for the following Set_Interface requests > to get ACK successfully. > > Signed-off-by: Jim Lin > --- > v2: xhci_clear_tt_buffer_complete: add static, shorter indentation > , remove its claiming in xhci.h > v3: Add description for clearing_tt (xhci.h) > > drivers/usb/host/xhci-ring.c | 28 ++++++++++++++++++++++++++++ > drivers/usb/host/xhci.c | 7 +++++++ > drivers/usb/host/xhci.h | 2 ++ > 3 files changed, 37 insertions(+) > > diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c > index 9215a28dad40..02b1ebad81e7 100644 > --- a/drivers/usb/host/xhci-ring.c > +++ b/drivers/usb/host/xhci-ring.c > @@ -1786,6 +1786,33 @@ struct xhci_segment *trb_in_td(struct xhci_hcd *xhci, > return NULL; > } > > +static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci, > + unsigned int slot_id, struct xhci_td *td) > +{ > + struct xhci_virt_device *dev; > + struct xhci_slot_ctx *slot_ctx; > + int saved_devnum; > + > + /* > + * As part of low/full-speed endpoint-halt processing > + * we must clear the TT buffer (USB 2.0 specification 11.17.5). > + */ > + if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) && > + (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) && > + !xhci->clearing_tt) { > + xhci->clearing_tt = 1; one xhci->clearing_tt under is not enough, there might be several HS hubs, or multi TT hubs with halted endpoints at the same time that need TT clearing. How about a flag per endpoint? For example Aadding a EP_CLEARING_TT flag for ep_state in struct xhci_virt_ep? just like EP_STOP_CMD_PENDING, or EP_HALTED > + dev = xhci->devs[slot_id]; > + slot_ctx = xhci_get_slot_ctx(xhci, dev->out_ctx); > + /* Update devnum temporarily for usb_hub_clear_tt_buffer */ > + saved_devnum = td->urb->dev->devnum; > + td->urb->dev->devnum = (int) le32_to_cpu(slot_ctx->dev_state) & > + DEV_ADDR_MASK; Changing the struct usb_device devnum on the fly seems like a bit of a hack, and probably causes issues elsewhere. Devnum is tied to uevents, usbfs, sysfs etc. We need another solution, some options: - Let usb_hub_clear_tt_buffer() figure out address and not just use devnum if host == xhci. - Add address to struct usb_device, (would have both address and devnum), use it when needed. - Provide address as parameter to usb_clear_tt_buffer() (api change, changes other host drivers) - Force devnum to be same as address, usb core can't choose address for xhci devices. -Mathias