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 903FAC433EF for ; Fri, 5 Nov 2021 13:32:17 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 54EE061101 for ; Fri, 5 Nov 2021 13:32:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 54EE061101 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=rowland.harvard.edu Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=yOMhGwLBGko/wuc2NcfMqzYlSmhqhb0qRGtt6qEOvkc=; b=CqK4NKd1YjQ4up BsJAntUdKsHzb7N+ojGnOrsqUzafuGlEwwCR9m7eEyfOfYPfVY45mVBLx1PeIPiOfyIhSmxB7rSzc y0udddOYjsK0d5rcHRcCHa07/1zraq4K3WiCYh7CkKIm46kXpnMpCbnGpzMUEBpPWcp8pMh3W10np ZvK96sM07L7hETxsBLYXafSxjyreZmnsOii8kg+IgIRIJrSjz1KGqak57GS9VqAdoNVQS6HBFfewK /X1XRNg0LAUU74usqCV23sbnKtp2vWIuC+stuCcEHIRFtUXkLSeXsx3OLfnyxWgRewcim8VSI6rWl ECU14kLsAXuJAGih8ijA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mizJ5-00BSQW-Vc; Fri, 05 Nov 2021 13:31:00 +0000 Received: from netrider.rowland.org ([192.131.102.5]) by bombadil.infradead.org with smtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mizJ0-00BSOt-PG for linux-arm-kernel@lists.infradead.org; Fri, 05 Nov 2021 13:30:56 +0000 Received: (qmail 1591166 invoked by uid 1000); 5 Nov 2021 09:30:50 -0400 Date: Fri, 5 Nov 2021 09:30:50 -0400 From: Alan Stern To: Greg Kroah-Hartman Cc: Mathias Nyman , "Walt Jr. Brake" , Mathias Nyman , Chunfeng Yun , Matthias Brugger , Nishad Kamdar , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Eddie Hung Subject: Re: [PATCH v2] usb: core: reduce power-on-good delay time of root hub Message-ID: <20211105133050.GA1590803@rowland.harvard.edu> References: <1618017645-12259-1-git-send-email-chunfeng.yun@mediatek.com> <5e907ccd-40bb-2ece-fe05-1a65a74f3aa2@gmail.com> <20211101140613.GC1456700@rowland.harvard.edu> <3cf46eaf-5443-30df-6d72-b92a6a518afc@linux.intel.com> <62d0ac30-f2b9-f58c-cb1e-215ccb455753@gmail.com> <13d55059-9f66-8599-54fc-46698bae41d1@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211105_063055_017142_A839A069 X-CRM114-Status: GOOD ( 32.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Nov 05, 2021 at 11:00:31AM +0100, Greg Kroah-Hartman wrote: > On Wed, Nov 03, 2021 at 10:37:33PM +0200, Mathias Nyman wrote: > > On 2.11.2021 22.29, Walt Jr. Brake wrote: > > > On 2/11/2021 17:05, Mathias Nyman wrote: > > >> On 1.11.2021 16.06, Alan Stern wrote: > > >>> On Sat, Oct 30, 2021 at 12:49:37PM +0800, Walt Jr. Brake wrote: > > >>>> This patch make USB 3.1 device cannot be detected, and I report th= e bug [1] > > >>>> to archlinux three month ago. Yesterday I try to fix it myself, an= d after I > > >>>> revert this patch, compile the kernel and test, it works. > > >>>> > > >>>> [1] https://bugs.archlinux.org/task/71660?project=3D1&pagenum=3D2 > > >>>> > > >>>> > > >>>> diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h > > >>>> index 22ea1f4f2d66..73f4482d833a 100644 > > >>>> --- a/drivers/usb/core/hub.h > > >>>> +++ b/drivers/usb/core/hub.h > > >>>> @@ -148,10 +148,8 @@ static inline unsigned hub_power_on_good_dela= y(struct > > >>>> usb_hub *hub) > > >>>> =A0=A0{ > > >>>> =A0=A0=A0=A0=A0=A0=A0=A0 unsigned delay =3D hub->descriptor->bPwrO= n2PwrGood * 2; > > >>>> > > >>>> -=A0=A0=A0=A0=A0=A0 if (!hub->hdev->parent) /* root hub */ > > >>>> -=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 return delay; > > >>>> -=A0=A0=A0=A0=A0=A0 else /* Wait at least 100 msec for power to be= come stable */ > > >>>> -=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 return max(delay, 100U= ); > > >>>> +=A0=A0=A0=A0=A0=A0 /* Wait at least 100 msec for power to become = stable */ > > >>>> +=A0=A0=A0=A0=A0=A0 return max(delay, 100U); > > >>>> =A0=A0} > > >>> Mathias: > > >>> > > >>> It looks like the bPwrOn2PwrGood value in xhci-hcd's hub descriptor= is > > >>> too small for some USB 3.1 devices. > > >>> > > >>> Can you look into this? > > >>> > > >>> Alan Stern > > >>> > > >> At first glance the xhci roothub bPwrOn2PwrGood value looks ok. > > >> xhci spec 5.4.8 states software should wait 20ms after asserting PP,= before > > >> attempting to change the state of the port. > > >> > > >> xhci driver sets desc->bPwrOn2PwrGood =3D 10; (2ms interval, so equa= ls 20ms ) > > >> > > >> We should probably get this working immediately, so maybe revert tha= t patch > > >> while looking into the rootcause. > > >> > > >> Walt Jr. Brake, instead of reverting that patch, could you test if c= hanging the > > >> xhci roothub bPwrOn2PwrGood value helps. > > >> > > >> diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub= .c > > >> index a3f875eea751..756231a55602 100644 > > >> --- a/drivers/usb/host/xhci-hub.c > > >> +++ b/drivers/usb/host/xhci-hub.c > > >> @@ -257,7 +257,7 @@ static void xhci_common_hub_descriptor(struct xh= ci_hcd *xhci, > > >> =A0 { > > >> =A0=A0=A0=A0=A0=A0=A0=A0 u16 temp; > > >> =A0 -=A0=A0=A0=A0=A0=A0 desc->bPwrOn2PwrGood =3D 10;=A0=A0=A0=A0=A0 = /* xhci section 5.4.9 says 20ms max */ > > >> +=A0=A0=A0=A0=A0=A0 desc->bPwrOn2PwrGood =3D 50;=A0=A0=A0=A0=A0 /* T= he 20ms in xhci 5.4.8 isn't enough for USB 3.1 */ > > >> =A0=A0=A0=A0=A0=A0=A0=A0 desc->bHubContrCurrent =3D 0; > > >> =A0 =A0=A0=A0=A0=A0=A0=A0=A0 desc->bNbrPorts =3D ports; > > >> > > >> Thanks > > >> -Mathias > > > = > > > Mathias: > > > = > > > Sorry to reply lately. I test with your patch, it works. > > > = > > > I also test with setting bPwrOn2PwrGood to 45, and it not work. > > > = > > > Seems that the minimal value should be 50 for this case. > > > = > > = > > Thanks for testing, and for checking that 90ms wait isn't enough > = > Can you send a "real" patch for this so I can get it into the tree soon > to resolve the regression? Also, it might make sense to move the desc->bPwrOn2PwrGood setting from = xhci_common_hub_descriptor into the speed-specific routines. For the = USB-2 root hub the value can remain set to 10; only the USB-3 root hub = needs to be changed. Alan Stern _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel