From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-941211-1518680744-2-13345644702459144280 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no ("Email failed DMARC policy for domain") X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org' X-Spam-charsets: plain='utf-8' X-IgnoreVacation: yes ("Email failed DMARC policy for domain") X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-usb-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1518680743; b=QlHlsK3iFzRE88P7OyZAE4LmCoZLbynkSMqLQXmteZ8YCNG mGq1t09MtEhS+ZfnVeqIbIwxoermsrEq7HSQZf8zJMIhVK//T02lKatSiv3TGshG dr8yOpxwqN+Y3AiuUozOrg9vRo2NIlVGyMXmXH3ekVV4r+ofEeyelcKRTGTAU7Fr wP4cg6N1U7vUcHrqsElL6XIbHn807NCCJ9JzSSvY2Jti3ZFOp8rF/MEUIdeCT4Id 5EC9ueSF4ogJ1aRJCKIzRltSj8lPo5kHcvjln/n7UOFz3GRoAKuGgQY/dIP7cKuj BAuDKqUn2wcDObEbMUiyhOoGKnxwg/oaleGbZAw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=subject:from:to:cc:references:message-id :date:mime-version:in-reply-to:content-type :content-transfer-encoding:sender:list-id; s=arctest; t= 1518680743; bh=kBd6FCLuA8TEAy2XHlgBVBzS250savd/ocafjX/gkyQ=; b=E tlybJzhQEEMDJHf9EFE6fYZGMBsAStKUuhopcVg0GByMMqzQaIaqE0BXAMEtTAWn YWLb68LcyyeQ77IG+RKDvsR7hz1Y3mdHEBPejUfAb8SvsXfN/C4szLxHLnGVuHqT gjSBhajbsQ/SIePv2tP/UPdob4BIKsBsAHvh8SnJK0fcGR5PoYTD+Ns2N6W+5rSC kh3efiVk4sFC9xxesoD6iK+wEXaQjsboYQD95jDcw36moVnoxqldH5DJdKAsWSHE P4Ou20h0A6oGtTqLNwb7L9su+5KGmwrTX9WjCohsHUQSS3I3PnmZNTnauEwvg856 U0wus96L+D7l19W8rHURw== ARC-Authentication-Results: i=1; mx3.messagingengine.com; arc=none (no signatures found); dkim=fail (body has been altered; 1024-bit rsa key sha256) header.d=ti.com header.i=@ti.com header.b=Y2jmDkCh x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=ti-com-17Q1; dmarc=fail (p=quarantine,has-list-id=yes,d=quarantine) header.from=ti.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-usb-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=ti.com header.result=pass header_is_org_domain=yes Authentication-Results: mx3.messagingengine.com; arc=none (no signatures found); dkim=fail (body has been altered; 1024-bit rsa key sha256) header.d=ti.com header.i=@ti.com header.b=Y2jmDkCh x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=ti-com-17Q1; dmarc=fail (p=quarantine,has-list-id=yes,d=quarantine) header.from=ti.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-usb-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=ti.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754899AbeBOHpM (ORCPT ); Thu, 15 Feb 2018 02:45:12 -0500 Received: from lelnx194.ext.ti.com ([198.47.27.80]:64364 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754851AbeBOHpL (ORCPT ); Thu, 15 Feb 2018 02:45:11 -0500 Subject: Re: [PATCH 2/2] usb: dwc3: drd: Fix lock-up on ID change during system suspend/resume From: Roger Quadros To: Manu Gautam , CC: , References: <1516626103-1969-1-git-send-email-rogerq@ti.com> <1516626103-1969-3-git-send-email-rogerq@ti.com> <522f639a-466f-ae72-745e-61cbcc6fbfc7@codeaurora.org> <557afc49-712d-9e70-7e4a-b7b3e74b7a50@ti.com> <8c4da216-7468-df31-01e3-644601421049@ti.com> Message-ID: Date: Thu, 15 Feb 2018 09:45:06 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-GB Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-usb-owner@vger.kernel.org X-Mailing-List: linux-usb@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Felipe, On 25/01/18 18:11, Roger Quadros wrote: > Hi, > > On 24/01/18 14:19, Roger Quadros wrote: >> On 23/01/18 14:41, Roger Quadros wrote: >>> Hi Manu, >>> >>> On 23/01/18 05:45, Manu Gautam wrote: >>>> Hi, >>>> >>>> >>>> On 1/22/2018 6:31 PM, Roger Quadros wrote: >>>>> Adding/removing host/gadget controller before .pm_complete() >>>>> causes a lock-up. Let's prevent any dual-role state change >>>>> between .pm_prepare() and .pm_complete() to fix this. >>>> >>>> What kind of lock-up are you seeing? Some hardware lockup or software deadlock? >>>> IMO using a freezable_wq for drd_work should address that? >>>> >>> >>> I was seeing a software deadlock. freezable_wq is a good idea. I'll try it out. >> >> using freezable_wq doesn't get rid of the deadlock. >> If I use freezable_wq plus add some delay before I do a dwc3_host_init() >> in the work function then it starts to work. >> >> As dependence on delay looks fragile so I'll stick to the current implementation >> based on .pm_prepare/complete(). >> > > So I was able to reproduce the lock up with my series as well. On further investigation > this is what I see. > > There are 2 different scenarios. > > 1) controller in host mode prior to system suspend and switches to device mode during resume. > > In this case when we call dwc3_host_exit() before tasks are thawed > xhci_plat_remove() seems to lock up at the second usb_remove_hcd() call. > This issue is resolved by using system_freezable_wq for the _dwc3_set_mode() function. > > > 2) controller in device mode prior to system suspend and switches to host mode during resume. > > In this case we sleep indefinitely in _dwc3_set_mode due to > dwc3_set_mode()->dwc3_gadget_exit()->usb_del_gadget_udc()->udc_stop()->dwc3_gadget_stop()->wait_event_lock_irq() > > This is not resolved by moving the dwc3_set_mode() call to .pm_complete() nor via the system_freezable_wq. > > One way I could fix this is like so. > > Felipe, could you please suggest a better way? > Maybe we need to do this in dwc3_gadget_exit() before calling usb_del_gadget_udc() ? Once you let me know your opinion I can revise this series. Thanks. > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > index b417d9a..0c903c1 100644 > --- a/drivers/usb/dwc3/core.c > +++ b/drivers/usb/dwc3/core.c > @@ -109,6 +109,7 @@ static void __dwc3_set_mode(struct work_struct *work) > struct dwc3 *dwc = work_to_dwc(work); > unsigned long flags; > int ret; > + int epnum; > > if (!dwc->desired_dr_role) > return; > @@ -124,6 +125,17 @@ static void __dwc3_set_mode(struct work_struct *work) > dwc3_host_exit(dwc); > break; > case DWC3_GCTL_PRTCAP_DEVICE: > + spin_lock_irqsave(&dwc->lock, flags); > + for (epnum = 2; epnum < DWC3_ENDPOINTS_NUM; epnum++) { > + struct dwc3_ep *dep = dwc->eps[epnum]; > + > + if (!dep) > + continue; > + > + dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING; > + } > + spin_unlock_irqrestore(&dwc->lock, flags); > + > dwc3_gadget_exit(dwc); > dwc3_event_buffers_cleanup(dwc); > break; > -- cheers, -roger Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. 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