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 D0BFBC433F5 for ; Fri, 5 Nov 2021 10:00:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B49F561284 for ; Fri, 5 Nov 2021 10:00:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232983AbhKEKDR (ORCPT ); Fri, 5 Nov 2021 06:03:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:50126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233025AbhKEKDN (ORCPT ); Fri, 5 Nov 2021 06:03:13 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 895036128E; Fri, 5 Nov 2021 10:00:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636106434; bh=9xqJCHW4+6GKO2Maqx5mkTpR7LQgTIZrxQah13VAIMs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=yxnYLAnDk2gTATOymrSa55+AdtgOYT/VlFyCEs6MrTfmzlmZYopR+ch/sCYYaln1u nRbkGRBUJlVewUH01DbDxcfIH7z6Yascv+Y5Dg0hecevCALFYnIFJx0y5hs52EEblV OaSPuUwE6cEDc3SnAD9BUBFKOW9y0AxM6gzKEGmk= Date: Fri, 5 Nov 2021 11:00:31 +0100 From: Greg Kroah-Hartman To: Mathias Nyman Cc: "Walt Jr. Brake" , Alan Stern , 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: 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-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <13d55059-9f66-8599-54fc-46698bae41d1@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 the bug [1] > >>>> to archlinux three month ago. Yesterday I try to fix it myself, and after I > >>>> revert this patch, compile the kernel and test, it works. > >>>> > >>>> [1] https://bugs.archlinux.org/task/71660?project=1&pagenum=2 > >>>> > >>>> > >>>> 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_delay(struct > >>>> usb_hub *hub) > >>>>   { > >>>>          unsigned delay = hub->descriptor->bPwrOn2PwrGood * 2; > >>>> > >>>> -       if (!hub->hdev->parent) /* root hub */ > >>>> -               return delay; > >>>> -       else /* Wait at least 100 msec for power to become stable */ > >>>> -               return max(delay, 100U); > >>>> +       /* Wait at least 100 msec for power to become stable */ > >>>> +       return max(delay, 100U); > >>>>   } > >>> 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 = 10; (2ms interval, so equals 20ms ) > >> > >> We should probably get this working immediately, so maybe revert that patch > >> while looking into the rootcause. > >> > >> Walt Jr. Brake, instead of reverting that patch, could you test if changing 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 xhci_hcd *xhci, > >>   { > >>          u16 temp; > >>   -       desc->bPwrOn2PwrGood = 10;      /* xhci section 5.4.9 says 20ms max */ > >> +       desc->bPwrOn2PwrGood = 50;      /* The 20ms in xhci 5.4.8 isn't enough for USB 3.1 */ > >>          desc->bHubContrCurrent = 0; > >>            desc->bNbrPorts = 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? thanks, greg k-h