From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-161521-1516896717-2-10272099028342653569 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 0.25, 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=1516896716; b=XnIheRF6mULbsU7kqjtQas1AbAG7W+hCrInCAkXduMjCpmp s1Mq+7F78MUOigjLAWKUTLkISQmfTQyxfvn90wEEhJXBqgaRAnhd5TJXjKdSaGdu rcfc42ur6S4QxdJOfDuXORuPMDaS/mIV2K2pjh5n48ljkxd0aMJKPpjf6SmuEJR5 kuZSIzHqjL/enBHZxPi1gwJo8zZxChLcwLiws23ukGrfOFA8juqtNOK2jMRr7Ol2 6kNRjwtdkWWlNkNyeh1kXnxewRQthn/0UULiSXfe3zkanQkL9yyDDD/AWKC16HyD uNm84ynzyhXDrcqbkP0cHrIhHIPTL/7s+Gi78Hg== 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= 1516896716; bh=5KPSXXjC3nGvH+TUq+1phC+x6lWQyG1OU+zzIZ0f0Kk=; b=e VC+6D20KdC6nVoJvRgqWwY6GNMGedmHD3qbTd4yt3nw/2Z64R4wIROQQyRICP6Gw Cu/tAQhdoUYGgs5fiVA9sDRxupjtIBbBL/EVwPAIzwzCcr3d6Or9D/1GodObywNu qHJP5CpmfdhqJYRTt2DNYfWzcjOlwHo87a6Jn86EXDLuHIPpdumz9hg8V60QQjw4 jqf2s9MwdBaztZBaQGeh0buSug500y6vydzpMevfRcUeUOOAv4q0+oPOI0+naZ9f UcxB7sHc4xt3q6TLNER4FPve1w2QEf165o7MTt8iUPKMkDz7jdE6DenQSDTyn3XK yJqEKwNe7m50IHFzaFYvQ== ARC-Authentication-Results: i=1; mx5.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=jjvyBZ2q 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: mx5.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=jjvyBZ2q 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 S1751120AbeAYQLm (ORCPT ); Thu, 25 Jan 2018 11:11:42 -0500 Received: from lelnx193.ext.ti.com ([198.47.27.77]:24028 "EHLO lelnx193.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750992AbeAYQLl (ORCPT ); Thu, 25 Jan 2018 11:11:41 -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, 25 Jan 2018 18:11:35 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <8c4da216-7468-df31-01e3-644601421049@ti.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-GB Content-Transfer-Encoding: 8bit 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: 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() ? 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. 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