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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84A64CDB474 for ; Tue, 17 Oct 2023 12:49:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343604AbjJQMt0 (ORCPT ); Tue, 17 Oct 2023 08:49:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46222 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233315AbjJQMtX (ORCPT ); Tue, 17 Oct 2023 08:49:23 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5ACD795; Tue, 17 Oct 2023 05:49:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1697546962; x=1729082962; h=message-id:date:mime-version:to:cc:references:from: subject:in-reply-to:content-transfer-encoding; bh=Vz3NwthM2agmUBZ7iXJuVbQIzPOwBgb/lOJg8aBciBU=; b=ITy8woyfnXVsWfzhNuc1XnbiGiKNvnkIyzctALCZFgSmvovpqSA59kWo F1l8g8TV+VMmuzyCWEb7F0KFaX1ONa6K17yBoxvCak4s0Pxw0bS9mPoLh mJhulnv5nMevl2Lqaatx/oOMFFq8dl6bIGFVx4uD0GV+4FAwQSCmGUEnB m0WrAGYtfA2cgpy9ZHdXnvEaidYhm6bf8gJT3TbgYDa8n6MQA5/QALdL1 TSXgETwLkQU4qrmdNJ8iIkUCwdSTNVek9m5O95d7WN/0TINvFM+BuxdZy 6yfG72tIfG7N3PgavmVE7J/WUgTgEmtMO+AR1K/t2ETtUKYowcnlJAbc3 Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10865"; a="385609331" X-IronPort-AV: E=Sophos;i="6.03,232,1694761200"; d="scan'208";a="385609331" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Oct 2023 05:49:22 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10866"; a="872553522" X-IronPort-AV: E=Sophos;i="6.03,232,1694761200"; d="scan'208";a="872553522" Received: from mattu-haswell.fi.intel.com (HELO [10.237.72.199]) ([10.237.72.199]) by fmsmga002.fm.intel.com with ESMTP; 17 Oct 2023 05:49:20 -0700 Message-ID: Date: Tue, 17 Oct 2023 15:50:48 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.13.0 Content-Language: en-US To: Wesley Cheng , mathias.nyman@intel.com, gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org References: <20231011220740.32297-1-quic_wcheng@quicinc.com> From: Mathias Nyman Subject: Re: [PATCH v4] usb: host: xhci: Avoid XHCI resume delay if SSUSB device is not present In-Reply-To: <20231011220740.32297-1-quic_wcheng@quicinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12.10.2023 1.07, Wesley Cheng wrote: > There is a 120ms delay implemented for allowing the XHCI host controller to > detect a U3 wakeup pulse. The intention is to wait for the device to retry > the wakeup event if the USB3 PORTSC doesn't reflect the RESUME link status > by the time it is checked. As per the USB3 specification: > > tU3WakeupRetryDelay ("Table 7-12. LTSSM State Transition Timeouts") > > This would allow the XHCI resume sequence to determine if the root hub > needs to be also resumed. However, in case there is no device connected, > or if there is only a HSUSB device connected, this delay would still affect > the overall resume timing. > > Since this delay is solely for detecting U3 wake events (USB3 specific) > then ignore this delay for the disconnected case and the HSUSB connected > only case. > > Signed-off-by: Wesley Cheng > --- > Depends-on: > https://lore.kernel.org/linux-usb/20230915143108.1532163-3-mathias.nyman@linux.intel.com/ > > changes in v4: > - Added change log between versions > > changes in v3: > - Modified logic to determine if a USB3.0 device is connected. Using the suspended_ports > and bus_suspended bitmasks. suspended_port is non-zero as ports are runtime suspended, > while bus_suspended is non-zero if system suspend occurs while ports are active. > > changes in v2: > - Looping across portsc to determine if there is a valid USB3 connection. > > drivers/usb/host/xhci.c | 20 +++++++++++++++++++- > 1 file changed, 19 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c > index e1b1b64a0723..1855cab1be56 100644 > --- a/drivers/usb/host/xhci.c > +++ b/drivers/usb/host/xhci.c > @@ -805,6 +805,18 @@ static void xhci_disable_hub_port_wake(struct xhci_hcd *xhci, > spin_unlock_irqrestore(&xhci->lock, flags); > } > > +/* > + * Utilize suspended_ports and bus_suspended to determine if USB3 device is > + * connected. The bus state bits are set by XHCI hub when root hub udev is > + * suspended. Used to determine if USB3 remote wakeup considerations need to > + * be accounted for during XHCI resume. > + */ > +static bool xhci_usb3_dev_connected(struct xhci_hcd *xhci) > +{ > + return !!xhci->usb3_rhub.bus_state.suspended_ports || > + !!xhci->usb3_rhub.bus_state.bus_suspended; > +} > + The function name xhci_usb3_dev_connected() is a bit misleading as it only returns true if there are _suspended_ USB 3 devices connected. I got rid of this helper and did some other minor modifications as well. Modified version is in my for-usb-next branch. https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=for-usb-next Let me know if these changes are ok. If yes, then I'll send it forward Thanks -Mathias