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=-19.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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=ham 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 C86BDC28B57 for ; Thu, 9 Sep 2021 06:52:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E95F61101 for ; Thu, 9 Sep 2021 06:52:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352635AbhIIGgt (ORCPT ); Thu, 9 Sep 2021 02:36:49 -0400 Received: from fllv0015.ext.ti.com ([198.47.19.141]:35748 "EHLO fllv0015.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244622AbhIIGgs (ORCPT ); Thu, 9 Sep 2021 02:36:48 -0400 Received: from lelv0266.itg.ti.com ([10.180.67.225]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 1896ZXkt054558; Thu, 9 Sep 2021 01:35:33 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1631169333; bh=4s7HGcdGS0K/ERh3FxmOpmro+p6ktKpCtpb6ApiFdwc=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=g842Wuf/+xYGujU3LKrZ+xN5LklgpNbwLTmmIl1rKpRAFyUO8WATb5ALKlsafijlG L/g248vbGCvoNMmpe/mTWdJhV/BYT4aCSXuthoCedIqI1yIoni0G//Y4OYH/sTL2UT gijCv/yZo0u1EoL9mDdZKVxC1uqatOuI7iSDgnY4= Received: from DLEE104.ent.ti.com (dlee104.ent.ti.com [157.170.170.34]) by lelv0266.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 1896ZX5F120167 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 9 Sep 2021 01:35:33 -0500 Received: from DLEE115.ent.ti.com (157.170.170.26) by DLEE104.ent.ti.com (157.170.170.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14; Thu, 9 Sep 2021 01:35:33 -0500 Received: from lelv0326.itg.ti.com (10.180.67.84) by DLEE115.ent.ti.com (157.170.170.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14 via Frontend Transport; Thu, 9 Sep 2021 01:35:33 -0500 Received: from [10.250.233.194] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 1896ZTdN062694; Thu, 9 Sep 2021 01:35:30 -0500 Subject: Re: [PATCH v3 1/3] usb: core: hcd: Add support for deferring roothub registration To: Alan Stern CC: Greg Kroah-Hartman , Mathias Nyman , , , , References: <20210908095312.985-1-kishon@ti.com> <20210908095312.985-2-kishon@ti.com> <20210908145146.GB603644@rowland.harvard.edu> From: Kishon Vijay Abraham I Message-ID: Date: Thu, 9 Sep 2021 12:05:28 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210908145146.GB603644@rowland.harvard.edu> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Alan, On 08/09/21 8:21 pm, Alan Stern wrote: > On Wed, Sep 08, 2021 at 03:23:10PM +0530, Kishon Vijay Abraham I wrote: >> It has been observed with certain PCIe USB cards (like Inateck connected >> to AM64 EVM or J7200 EVM) that as soon as the primary roothub is >> registered, port status change is handled even before xHC is running >> leading to cold plug USB devices not detected. For such cases, registering >> both the root hubs along with the second HCD is required. Add support for >> deferring roothub registration in usb_add_hcd(), so that both primary and >> secondary roothubs are registered along with the second HCD. >> >> CC: stable@vger.kernel.org # 5.4+ >> Signed-off-by: Kishon Vijay Abraham I >> Suggested-by: Mathias Nyman >> Tested-by: Chris Chiu >> --- >> drivers/usb/core/hcd.c | 30 ++++++++++++++++++++++++------ >> include/linux/usb/hcd.h | 2 ++ >> 2 files changed, 26 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c >> index 0f8b7c93310e..30bbf4ac4284 100644 >> --- a/drivers/usb/core/hcd.c >> +++ b/drivers/usb/core/hcd.c >> @@ -2775,6 +2775,7 @@ int usb_add_hcd(struct usb_hcd *hcd, >> { >> int retval; >> struct usb_device *rhdev; >> + struct usb_hcd *shared_hcd; >> >> if (!hcd->skip_phy_initialization && usb_hcd_is_primary_hcd(hcd)) { >> hcd->phy_roothub = usb_phy_roothub_alloc(hcd->self.sysdev); >> @@ -2935,13 +2936,26 @@ int usb_add_hcd(struct usb_hcd *hcd, >> goto err_hcd_driver_start; >> } >> >> + /* starting here, usbcore will pay attention to the shared HCD roothub */ >> + shared_hcd = hcd->shared_hcd; >> + if (!usb_hcd_is_primary_hcd(hcd) && shared_hcd && HCD_DEFER_RH_REGISTER(shared_hcd)) { >> + retval = register_root_hub(shared_hcd); >> + if (retval != 0) >> + goto err_register_root_hub; >> + >> + if (shared_hcd->uses_new_polling && HCD_POLL_RH(shared_hcd)) >> + usb_hcd_poll_rh_status(shared_hcd); >> + } >> + >> /* starting here, usbcore will pay attention to this root hub */ >> - retval = register_root_hub(hcd); >> - if (retval != 0) >> - goto err_register_root_hub; >> + if (!HCD_DEFER_RH_REGISTER(hcd)) { >> + retval = register_root_hub(hcd); >> + if (retval != 0) >> + goto err_register_root_hub; >> >> - if (hcd->uses_new_polling && HCD_POLL_RH(hcd)) >> - usb_hcd_poll_rh_status(hcd); >> + if (hcd->uses_new_polling && HCD_POLL_RH(hcd)) >> + usb_hcd_poll_rh_status(hcd); >> + } >> >> return retval; >> >> @@ -2985,6 +2999,7 @@ EXPORT_SYMBOL_GPL(usb_add_hcd); >> void usb_remove_hcd(struct usb_hcd *hcd) >> { >> struct usb_device *rhdev = hcd->self.root_hub; >> + unsigned rh_registered; > > This really should be a bool, not an unsigned. (Relatively unimportant.) > >> dev_info(hcd->self.controller, "remove, state %x\n", hcd->state); >> >> @@ -2995,6 +3010,8 @@ void usb_remove_hcd(struct usb_hcd *hcd) >> >> dev_dbg(hcd->self.controller, "roothub graceful disconnect\n"); >> spin_lock_irq (&hcd_root_hub_lock); >> + if (hcd->rh_registered == 1) >> + rh_registered = 1; > > Just say: rh_registered = hcd->rh_registered > >> hcd->rh_registered = 0; >> spin_unlock_irq (&hcd_root_hub_lock); >> >> @@ -3004,7 +3021,8 @@ void usb_remove_hcd(struct usb_hcd *hcd) >> cancel_work_sync(&hcd->died_work); >> >> mutex_lock(&usb_bus_idr_lock); >> - usb_disconnect(&rhdev); /* Sets rhdev to NULL */ >> + if (rh_registered == 1) > > Just say: if (rh_registered) > >> + usb_disconnect(&rhdev); /* Sets rhdev to NULL */ > > Didn't the compiler warn about using a possibly uninitialized variable? I didn't see any. Possibly the warning levels are not correctly set in my setup. Will address your comment and send the patch. Thank You, Kishon > > The overall logic looks okay, apart from this one point. > > Alan Stern > >> mutex_unlock(&usb_bus_idr_lock); >> >> /* >> diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h >> index 548a028f2dab..2c1fc9212cf2 100644 >> --- a/include/linux/usb/hcd.h >> +++ b/include/linux/usb/hcd.h >> @@ -124,6 +124,7 @@ struct usb_hcd { >> #define HCD_FLAG_RH_RUNNING 5 /* root hub is running? */ >> #define HCD_FLAG_DEAD 6 /* controller has died? */ >> #define HCD_FLAG_INTF_AUTHORIZED 7 /* authorize interfaces? */ >> +#define HCD_FLAG_DEFER_RH_REGISTER 8 /* Defer roothub registration */ >> >> /* The flags can be tested using these macros; they are likely to >> * be slightly faster than test_bit(). >> @@ -134,6 +135,7 @@ struct usb_hcd { >> #define HCD_WAKEUP_PENDING(hcd) ((hcd)->flags & (1U << HCD_FLAG_WAKEUP_PENDING)) >> #define HCD_RH_RUNNING(hcd) ((hcd)->flags & (1U << HCD_FLAG_RH_RUNNING)) >> #define HCD_DEAD(hcd) ((hcd)->flags & (1U << HCD_FLAG_DEAD)) >> +#define HCD_DEFER_RH_REGISTER(hcd) ((hcd)->flags & (1U << HCD_FLAG_DEFER_RH_REGISTER)) >> >> /* >> * Specifies if interfaces are authorized by default >> -- >> 2.17.1 >>