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 16090C433FE for ; Mon, 9 May 2022 03:49:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233383AbiEIDvu (ORCPT ); Sun, 8 May 2022 23:51:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43898 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229689AbiEIDm6 (ORCPT ); Sun, 8 May 2022 23:42:58 -0400 Received: from alexa-out-sd-01.qualcomm.com (alexa-out-sd-01.qualcomm.com [199.106.114.38]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8608AD11F; Sun, 8 May 2022 20:39:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1652067541; x=1683603541; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=Eec18//IsPwyC++u7RUnbqlmOOXMwJSxguy1wuaYhpw=; b=we78HVW9HlOQ/CHVIvPONMrWOEGsHpG9ajgN3+52cChGpxoq7sE2QWfd 2tZuSSPTFCrPxCTZD5mGFfA47RMAmrtnxhSLio9EKj+2wmPbvv2F4RBht /xuSguEi6tos0JA23AJfVDJHOnADtepgXVed+iRan6Y3Bd+7lv/EaipsR U=; Received: from unknown (HELO ironmsg03-sd.qualcomm.com) ([10.53.140.143]) by alexa-out-sd-01.qualcomm.com with ESMTP; 08 May 2022 20:38:53 -0700 X-QCInternal: smtphost Received: from nasanex01c.na.qualcomm.com ([10.47.97.222]) by ironmsg03-sd.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2022 20:38:53 -0700 Received: from nalasex01a.na.qualcomm.com (10.47.209.196) by nasanex01c.na.qualcomm.com (10.47.97.222) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Sun, 8 May 2022 20:38:53 -0700 Received: from hu-pkondeti-hyd.qualcomm.com (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Sun, 8 May 2022 20:38:47 -0700 Date: Mon, 9 May 2022 09:08:43 +0530 From: Pavan Kondeti To: Matthias Kaehlcke CC: Krishna Kurapati , Krzysztof Kozlowski , Rob Herring , "Andy Gross" , Bjorn Andersson , Greg Kroah-Hartman , Felipe Balbi , Stephen Boyd , Doug Anderson , Mathias Nyman , , , , , , , , Subject: Re: [v15 2/6] usb: host: xhci-plat: Enable wakeup based on children wakeup status Message-ID: <20220509033843.GB9170@hu-pkondeti-hyd.qualcomm.com> References: <1651740973-7944-1-git-send-email-quic_kriskura@quicinc.com> <1651740973-7944-3-git-send-email-quic_kriskura@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nalasex01a.na.qualcomm.com (10.47.209.196) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 06, 2022 at 08:36:31AM -0700, Matthias Kaehlcke wrote: > On Thu, May 05, 2022 at 02:26:09PM +0530, Krishna Kurapati wrote: > > device_wakeup_path() tells if any of the children devices needs > > wakeup. Use this hint to enable/disable wakeup of our device. This > > helps the parent device of xhci-plat (like sysdev) to retrieve > > the wakeup setting via device_wakeup_path(). > > > > Signed-off-by: Krishna Kurapati > > --- > > drivers/usb/host/xhci-plat.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c > > index 649ffd8..ad585fa 100644 > > --- a/drivers/usb/host/xhci-plat.c > > +++ b/drivers/usb/host/xhci-plat.c > > @@ -415,6 +415,14 @@ static int __maybe_unused xhci_plat_suspend(struct device *dev) > > if (pm_runtime_suspended(dev)) > > pm_runtime_resume(dev); > > > > + if (device_wakeup_path(dev)) { > > + if (!device_may_wakeup(dev)) > > + device_wakeup_enable(dev); > > + } else { > > + if (device_may_wakeup(dev)) > > + device_wakeup_disable(dev); > > + } > > This code is not self-explantatory and deserves a comment. > > Enabling/disabling wakeup for the purpose if signalling is a bit of a > hack. It might be an acceptable hack as long as it has no side effects. > However with the current implementation the wakeup state of the xHCI can > be different after resuming than it was before going to suspend: > > after boot > grep -h xhci /sys/class/wakeup/*/name > => xhci-hcd.14.auto > > after suspend w/o wakeup capable device > grep -h xhci /sys/class/wakeup/*/name > => no results > > after suspend with wakeup capable device > grep -h xhci /sys/class/wakeup/*/name > => xhci-hcd.14.auto > > The hack shouldn't alter the wakeup state 'persistently', i.e. you'll have > to restore it on resume, as in Pavan does in his reply to '[PATCH v14 2/7] > PM / wakeup: Add device_children_wakeup_capable()' (it needs to be done > conditionally though). I am worried that we are not doing the right thing here. why should the xhci-plat goes against the wishes of the user space policy here? Can we NOT just do anything here? If some one wants xhci-plat to wakeup all the time, dwc3 will be configured to wakeup the system provided that the support is available. This way we don't break any existing users of xhci-plat i.e not enabling wakeup from the kernel. Thanks, Pavan