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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C1D5C433F5 for ; Mon, 11 Oct 2021 07:22:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5CF0260EC0 for ; Mon, 11 Oct 2021 07:22:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234470AbhJKHYI (ORCPT ); Mon, 11 Oct 2021 03:24:08 -0400 Received: from mail.loongson.cn ([114.242.206.163]:34838 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S233790AbhJKHYH (ORCPT ); Mon, 11 Oct 2021 03:24:07 -0400 Received: from [10.180.13.145] (unknown [10.180.13.145]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9DxX2oY5mNhxfQXAA--.22179S2; Mon, 11 Oct 2021 15:22:00 +0800 (CST) Subject: Re: [PATCH v3] usb: ohci: add check for host controller functional states From: zhuyinbo To: Alan Stern Cc: Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Patchwork Bot References: <1633677970-10619-1-git-send-email-zhuyinbo@loongson.cn> <20211008142639.GA721194@rowland.harvard.edu> <7a505fc4-ec47-ac83-633f-7a5251bd5f82@loongson.cn> <20211009193901.GA753830@rowland.harvard.edu> Message-ID: <8ef37927-c815-99ac-28b5-940d66c904d0@loongson.cn> Date: Mon, 11 Oct 2021 15:22:00 +0800 User-Agent: Mozilla/5.0 (X11; Linux mips64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-CM-TRANSID: AQAAf9DxX2oY5mNhxfQXAA--.22179S2 X-Coremail-Antispam: 1UD129KBjvJXoWxKr4rKFyfKr4UKF1rKF4kJFb_yoW7Kr15pF 4xKa13KrWDAr10vw17tr1ktF9YkrW7G3y5WryDGFy8AwnIqryaqr4IgrWj9aykWrWfG3W7 ZF1Utay7uw1UCFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvFb7Iv0xC_Kw4lb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rw A2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xII jxv20xvEc7CjxVAFwI0_Cr0_Gr1UM28EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwV C2z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC 0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr 1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcVAKI48JMxk0xIA0c2IEe2xFo4CEbIxvr21l c2xSY4AK6svPMxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I 8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUAVWU twCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x 0267AKxVWUJVW8JwCI42IY6xAIw20EY4v20xvaj40_WFyUJVCq3wCI42IY6I8E87Iv67AK xVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvj xUgg_TUUUUU X-CM-SenderInfo: 52kx5xhqerqz5rrqw2lrqou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2021/10/11 下午1:10, zhuyinbo 写道: > > 在 2021/10/10 上午3:39, Alan Stern 写道: >> On Sat, Oct 09, 2021 at 10:01:25AM +0800, zhuyinbo wrote: >>> 在 2021/10/8 下午10:26, Alan Stern 写道: >>>> On Fri, Oct 08, 2021 at 03:26:10PM +0800, Yinbo Zhu wrote: >>>>> The usb states of ohci controller include UsbOperational, UsbReset, >>>>> UsbSuspend and UsbResume. Among them, only the UsbOperational state >>>>> supports launching the start of frame for host controller according >>>>> the ohci protocol spec, but in S3/S4 press test procedure, it may >>>> Nobody reading this will know what "S3/S4 press test procedure" means. >>>> You have to explain it, or use a different name that people will >>>> understand. >>> okay, I got it. >>>>> happen that the start of frame was launched in other usb states and >>>>> cause ohci works abnormally then kernel will allways report rcu >>>>> call trace. This patch was to add check for host controller >>>>> functional states and if it is not UsbOperational state that need >>>>> set INTR_SF in intrdisable register to ensure SOF Token generation >>>>> was been disabled. >>>> This doesn't make sense.  You already mentioned that only the >>>> UsbOperational state supports sending start-of-frame packets.  So >>>> if the >>>> controller is in a different state then it won't send these packets, >>>> whether INTR_SF is enabled or not. >>>> >>>> What problem are you really trying to solve? >>> Only UsbOperational state supports sending start-of-frame packets, >>> but in >>> fact, in S3/S4 press test procedure, >>> >>> usb in non-UsbOperational state that send start-of-frame packets but hc >>> driver doesn't deal with this frame. and hc will >>> >>> allways lauched the SOF for finishing the frame, the cpu will hand >>> this sof >>> interrupt and doesn't deal with time interrupt >>> >>> that will cause rcu call trace then system doesn't suspend to >>> memory/disk. >> I still don't understand. >> >> Are you saying that your OHCI controller behaves badly because it sends >> SOF packets even when the state is different from UsbOperational? > > HC will allways report the SoF interrupt in the all time when HC was > not in NO-UsbOperation state. > > and no WritebackDoneHead interrupt that is the issue phenomenon. and > this situation is badly state for ohci. > >> >>> Hi Alan Stern, >>> >>>      even though ed_rm_list is non-NULL, if hc in non-UsbOperation >>> state set >>> SoF status in usbsts register that is illegal, >>> >>> at this time hcd doesn't need care URB whether finished, because hc had >>> into a wrong state. even thoug it doesn't has this patch, >>> >>> URB was not be able to finish when hc in above worng state. except >>> software >>> can intervence this wrong state. but the SoF bit of usbsts >>> >>> register was set by HC, and this action will happen always !!! software >>> clear SoF state I think it isn't make sense. software only disable SoF >>> >>> interrupt to fix HC wrong state. >> This problem happens when you go into S3 or S4 suspend, right? So you >> should fix the problem by disabling INTR_SF when the root hub is >> suspended.  Try adding >> >>     /* All ED unlinks should be finished, no need for SOF interrupts */ >>     ohci_writel(ohci, OHCI_INTR_SF, &ohci->regs->intrdisable); >> >> into ohci_rh_suspend(), just before the update_done_list() call.  If you >> add this then INTR_SF will not be enabled during S3 or S4 suspend, so >> the problem shouldn't occur.  Does that work for you? > > The system doesn't suspend to disk completely by my test result and hc > will always produce SoF interrupt. > > I encountered SoF interrupt  issue when HC in UsbSuspend state. and I > think when hc in > > UsbResume/UsbRest/ SoF interrupt issue may be happen so I disable > INTR_SF in ohci_irq. > > So I think disable INTR_SF in suspend function which this way isn't > good for me. > >     In addition, I hope my patch was not only fix the bug i > encountered and it can limit HC into badly state and it should be the > > base limit condition and prevent more unknown problems.  In fact, HC > doesn't deal with ed/td list and done list by the ohci spec, so > > I think my patch has no risk for ohci. > >       by the way, root hub state isn't completely same with HC, but > the root hub reset and resume signaling are controlled by the hcfs bits. > > and hcd can set hcfs to decide hc usb state, so I judge whether set > SF_INT to interrupt disable register only depend on HC state. And I have a test, ohci_rh_suspend was called that HC state as gerneral was also UsbOperational state whatever do s3/s4 test or power on to boot kernel. but HCD record it as suspend state on root hub at this time. > >> >>>        In additon, when kernel include my patch, that it does't >>> happen about >>> what you descriped that driver will not be able to finish unlinging >>> URBs. >>> >>> Because above issue happen in S3/S4(Suspend to disk/Suspend to mem) >>> test >>> procedure, if ed_rm_lis is no-NULL but my patch disable SoF interrupt. >>> >>> then when S3/S4 recovery to cpu idle state that usb resume will be >>> called, >>> reume function has following logic, URB will continue to be processed. >>> >>>        static int ohci_rh_resume (struct ohci_hcd *ohci) >>> >>>       { >>> >>>          ... >>> >>>          242         if (ohci->ed_rm_list) >>>          243                 ohci_writel (ohci, OHCI_INTR_SF, >>> &ohci->regs->intrenable); >>> >>>         ... >>> >>>        } >> I'm worried that your patch may disable INTR_SF even when the controller >> has not gone into S3 or S4 suspend.  Maybe this won't cause problems, >> but it's better to be safe and do the disable _only_ when a suspend >> occurs. >> >> Alan Stern > > Hi  Alan Stern, > >     According to the previous statement, I think my patch has no risk > on ohci. > > > >