From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751009AbdALPji (ORCPT ); Thu, 12 Jan 2017 10:39:38 -0500 Received: from lelnx194.ext.ti.com ([198.47.27.80]:53817 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750936AbdALPjh (ORCPT ); Thu, 12 Jan 2017 10:39:37 -0500 Subject: Re: [PATCH] usb: hcd: initialize hcd->flags to 0 when rm hcd To: Alan Stern References: CC: William Wu , , , , , , , , , , William wu From: Roger Quadros Message-ID: Date: Thu, 12 Jan 2017 17:38:47 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/01/17 17:33, Alan Stern wrote: > On Thu, 12 Jan 2017, Roger Quadros wrote: > >> William, >> >> On 12/01/17 14:03, William Wu wrote: >>> From: William wu >>> >>> On some platforms(e.g. rk3399 board), we can call hcd_add/remove >>> consecutively without calling usb_put_hcd/usb_create_hcd in between, >>> so hcd->flags can be stale. >>> >>> If the HC dies due to whatever reason then without this patch we get >>> the below error on next hcd_add. >>> >>> [173.296154] xhci-hcd xhci-hcd.2.auto: HC died; cleaning up >>> [173.296209] xhci-hcd xhci-hcd.2.auto: xHCI Host Controller >>> [173.296762] xhci-hcd xhci-hcd.2.auto: new USB bus registered, assigned bus number 6 >>> [173.296931] usb usb6: We don't know the algorithms for LPM for this host, disabling LPM. >>> [173.297179] usb usb6: New USB device found, idVendor=1d6b, idProduct=0003 >>> [173.297203] usb usb6: New USB device strings: Mfr=3, Product=2, SerialNumber=1 >>> [173.297222] usb usb6: Product: xHCI Host Controller >>> [173.297240] usb usb6: Manufacturer: Linux 4.4.21 xhci-hcd >>> [173.297257] usb usb6: SerialNumber: xhci-hcd.2.auto >>> [173.298680] hub 6-0:1.0: USB hub found >>> [173.298749] hub 6-0:1.0: 1 port detected >>> [173.299382] rockchip-dwc3 usb@fe800000: USB HOST connected >>> [173.395418] hub 5-0:1.0: activate --> -19 >>> [173.603447] irq 228: nobody cared (try booting with the "irqpoll" option) >>> [173.603493] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.21 #9 >>> [173.603513] Hardware name: Google Kevin (DT) >>> [173.603531] Call trace: >>> [173.603568] [] dump_backtrace+0x0/0x160 >>> [173.603596] [] show_stack+0x20/0x28 >>> [173.603623] [] dump_stack+0x90/0xb0 >>> [173.603650] [] __report_bad_irq+0x48/0xe8 >>> [173.603674] [] note_interrupt+0x1e8/0x28c >>> [173.603698] [] handle_irq_event_percpu+0x1d4/0x25c >>> [173.603722] [] handle_irq_event+0x4c/0x7c >>> [173.603748] [] handle_fasteoi_irq+0xb4/0x124 >>> [173.603777] [] generic_handle_irq+0x30/0x44 >>> [173.603804] [] __handle_domain_irq+0x90/0xbc >>> [173.603827] [] gic_handle_irq+0xcc/0x188 >>> ... >>> [173.604500] [] el1_irq+0x80/0xf8 >>> [173.604530] [] cpu_startup_entry+0x38/0x3cc >>> [173.604558] [] rest_init+0x8c/0x94 >>> [173.604585] [] start_kernel+0x3d0/0x3fc >>> [173.604607] [<0000000000b16000>] 0xb16000 >>> [173.604622] handlers: >>> [173.604648] [] usb_hcd_irq >>> [173.604673] Disabling IRQ #228 >>> >>> Signed-off-by: William wu >>> Signed-off-by: William wu >>> --- >>> drivers/usb/core/hcd.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c >>> index 479e223..612fab6 100644 >>> --- a/drivers/usb/core/hcd.c >>> +++ b/drivers/usb/core/hcd.c >>> @@ -3017,6 +3017,7 @@ void usb_remove_hcd(struct usb_hcd *hcd) >>> } >>> >>> usb_put_invalidate_rhdev(hcd); >>> + hcd->flags = 0; >>> } >>> EXPORT_SYMBOL_GPL(usb_remove_hcd); >>> >>> >> I suggest to initialize hcd->flags to 0 in usb_add_hcd() instead. >> >> cheers, >> -roger > > Roger, didn't you originally propose this very same patch in > > http://marc.info/?l=linux-usb&m=146556415503583&w=2 > > (and of course, the earlier versions before v10)? What happened to it? Alan, You are right. That patch got lost in the ML. Looks like I didn't push it hard enough and then forgot about it. Sorry. William, You don't need to do any changes. My earlier version was clearing the flag in usb_add_hcd() and I guess Alan suggested to move it to usb_remove_hcd(). So your patch is good. You can add my. Acked-by: Roger Quadros cheers, -roger