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=-15.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 8CC89C48BE0 for ; Thu, 10 Jun 2021 20:28:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68C6B613CA for ; Thu, 10 Jun 2021 20:28:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230188AbhFJUaH (ORCPT ); Thu, 10 Jun 2021 16:30:07 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:43328 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229941AbhFJUaG (ORCPT ); Thu, 10 Jun 2021 16:30:06 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1623356889; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: References: Cc: To: From: Subject: Sender; bh=iTxrC4mF4w/Quqh7s+egckNZ4to2Zt81mjmqcIDFHTE=; b=dV/HjaYFOyr5ZAnPrcWCkZcN4Disyyqb5LTO+C17rrFtN4ANO1ig82YUCbeXnaSFwssauXU5 gqYj0GjcxEj/emuxuCF8QrguWksE65ExT3sv0yYP3uJiib+JIj4Zs5fMFHUxI2wxPxnD5wxN GKwGMxq1WL6XzhW9TuumNoT45P8= X-Mailgun-Sending-Ip: 69.72.43.7 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n06.prod.us-west-2.postgun.com with SMTP id 60c275ceed59bf69cc763aab (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 10 Jun 2021 20:27:58 GMT Sender: wcheng=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 7B0C9C4323A; Thu, 10 Jun 2021 20:27:57 +0000 (UTC) Received: from [10.110.41.194] (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: wcheng) by smtp.codeaurora.org (Postfix) with ESMTPSA id D4A37C433F1; Thu, 10 Jun 2021 20:27:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org D4A37C433F1 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=wcheng@codeaurora.org Subject: Re: [PATCH] usb: dwc3: gadget: Disable gadget IRQ during pullup disable From: Wesley Cheng To: Felipe Balbi , gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, jackp@codeaurora.org References: <1621571037-1424-1-git-send-email-wcheng@codeaurora.org> <87h7i60ye8.fsf@kernel.org> <724ba69a-8c67-4b4b-3e6a-a5834b09e6e1@codeaurora.org> Message-ID: Date: Thu, 10 Jun 2021 13:27:54 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: <724ba69a-8c67-4b4b-3e6a-a5834b09e6e1@codeaurora.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/10/2021 11:21 AM, Wesley Cheng wrote: > > > On 6/10/2021 4:09 AM, Felipe Balbi wrote: >> Wesley Cheng writes: >> >>> Current sequence utilizes dwc3_gadget_disable_irq() alongside >>> synchronize_irq() to ensure that no further DWC3 events are generated. >>> However, the dwc3_gadget_disable_irq() API only disables device >>> specific events. Endpoint events can still be generated. Briefly >>> disable the interrupt line, so that the cleanup code can run to >>> prevent device and endpoint events. (i.e. __dwc3_gadget_stop() and >>> dwc3_stop_active_transfers() respectively) >>> >>> Without doing so, it can lead to both the interrupt handler and the >>> pullup disable routine both writing to the GEVNTCOUNT register, which >>> will cause an incorrect count being read from future interrupts. >>> >>> Fixes: ae7e86108b12 ("usb: dwc3: Stop active transfers before halting the controller") >>> Signed-off-by: Wesley Cheng >>> --- >>> drivers/usb/dwc3/gadget.c | 11 +++++------ >>> 1 file changed, 5 insertions(+), 6 deletions(-) >>> >>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c >>> index 49ca5da..89aa9ac 100644 >>> --- a/drivers/usb/dwc3/gadget.c >>> +++ b/drivers/usb/dwc3/gadget.c >>> @@ -2260,13 +2260,10 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on) >>> } >>> >>> /* >>> - * Synchronize any pending event handling before executing the controller >>> - * halt routine. >>> + * Synchronize and disable any further event handling while controller >>> + * is being enabled/disabled. >>> */ >>> - if (!is_on) { >>> - dwc3_gadget_disable_irq(dwc); >>> - synchronize_irq(dwc->irq_gadget); >>> - } >>> + disable_irq(dwc->irq_gadget); >>> >>> spin_lock_irqsave(&dwc->lock, flags); >> >> spin_lock_irqsave() is already disabling interrupt, right? Why do we >> need another call to disable_irq()? >> > > Hi Felipe, > > Yes, I remember you brought up that point as well before. So when I > checked the logs (USB and scheduler ftrace) for this issue, I clearly > saw that we were handling a soft disconnect on CPU3 and then an DWC3 IRQ > being scheduled into CPU0. Last time we discussed, I mentioned that > spin_lock_irqsave() only disables interrupts on that particular CPU the > thread is running on. > Hi Felipe, Let me share the ftrace snippets as well: USB FTRACE: -0 [002] 304.567900: dwc3_gadget_ep_cmd name=ep0out cmd=1030 param0=0 param1=4026523648 param2=0 cmd_status=0 -0 [004] 304.583225: dwc3_gadget_ep_cmd name=ep1out cmd=134152 param0=0 param1=0 param2=0 cmd_status=0 //We don't have any logging in pullup disable, but this is when that occurs, as we start to see -ESHUTDOWN statuses due to stop active transfer. -0 [004] 304.583237: dwc3_gadget_giveback name=ep1out req=1243650560 actual=0 length=16384 status=4294967188 zero=0 short_not_ok=0 no_interrupt=0 -0 [004] 304.583275: dwc3_gadget_giveback name=ep1out req=1243645440 actual=0 length=16384 status=4294967188 zero=0 short_not_ok=0 no_interrupt=0 -0 [004] 304.583282: dwc3_gadget_giveback name=ep1out req=1243648256 actual=0 length=16384 status=4294967188 zero=0 short_not_ok=0 no_interrupt=0 -0 [004] 304.583312: dwc3_gadget_giveback name=ep1out req=4075146240 actual=0 length=16384 status=4294967188 zero=0 short_not_ok=0 no_interrupt=0 ... //USB gadget disconnect is printed AFTER the pullup(0) routine is complete. -0 [004] 304.584240: usb_gadget_disconnect speed=3 max_speed=6 state=7 mA=500 sg_supported=1 is_otg=0 is_a_peripheral=0 b_hnp_enable=0 a_hnp_support=0 hnp_polling_support=0 host_request_flag=0 quirk_ep_out_aligned_size=0 quirk_altset_not_supp=0 quirk_stall_not_supp=0 quirk_zlp_not_supp=0 is_selfpowered=0 deactivated=0 connected=1 ret=4294967186 --------------------------------------------------------- CPU2 SCHED FTRACE: kworker/u16:5-192 [002] 304.583354: irq_handler_entry irq=343 name=dwc3-msm kworker/u16:5-192 [002] 304.583356: irq_handler_exit irq=343 ret=0 kworker/u16:5-192 [002] 304.583358: irq_handler_entry irq=343 name=dwc3 kworker/u16:5-192 [002] 304.583366: irq_handler_exit irq=343 ret=2 kworker/u16:5-192 [002] 304.583377: sched_wakeup comm=irq/343-dwc3 pid=20174 prio=100 success=1 target_cpu=2 kworker/u16:5-192 [002] 304.583411: sched_switch: prev_comm=kworker/u16:5 prev_pid=192 prev_prio=120 prev_state=R ==> next_comm=irq/343-dwc3 next_pid=20174 next_prio=100 irq/343-dwc3-20174 [002] 304.583454: irq_handler_entry irq=343 name=dwc3-msm irq/343-dwc3-20174 [002] 304.583455: irq_handler_exit irq=343 ret=0 irq/343-dwc3-20174 [002] 304.583458: irq_handler_entry irq=343 name=dwc3 irq/343-dwc3-20174 [002] 304.583465: irq_handler_exit irq=343 ret=2 So if we assume that the point of error happens @ 304.567900 due to the below points: - DWC3 pullup disable routine synchronized IRQs (w/ previous logic) before calling stop active transfers. - DWC3 request statuses shows ESHUTDOWN, which occurs during stop active transfer, as we call giveback w/ that error code Then we can see that on CPU2, we're still getting DWC3 core IRQs, and DWC3 IRQ handler is returning --> 2, which is IRQ_WAKE_THREAD. Thanks Wesley Cheng -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project