Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756021Ab3D1BwE (ORCPT ); Sat, 27 Apr 2013 21:52:04 -0400 Received: from g5t0006.atlanta.hp.com ([15.192.0.43]:14050 "EHLO g5t0006.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753894Ab3D1BwB (ORCPT ); Sat, 27 Apr 2013 21:52:01 -0400 Message-ID: <517C808A.2060502@hp.com> Date: Sun, 28 Apr 2013 09:51:06 +0800 From: ZhenHua User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:19.0) Gecko/20130117 Thunderbird/19.0 MIME-Version: 1.0 To: Alan Stern CC: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] driver,usb: Fix a warning in uhci-hcd driver References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2919 Lines: 73 On 04/27/2013 11:14 PM, Alan Stern wrote: > On Sat, 27 Apr 2013, ZhenHua wrote: > >> On 04/27/2013 12:51 AM, Alan Stern wrote: >>> On Fri, 26 Apr 2013, ZhenHua wrote: >>> >>>> There is a function wait_for_HP() in uhci-hub.c. In this >>>> patch, it is used in suspend_rh(), I think this can be a >>>> solution. And I have tested this patch, it can fix the bug. >>>> >>>> I think there is another patch needed. As Alan said in another >>>> mail, in the UHCI_RH_RUNNING_NODEVS case, it should not be stopped >>>> if the uhci device is HP iLo virtual usb. >>> I believe that if you change the UHCI_RH_RUNNING_NODEVS case, you will >>> find that this patch (calling wait_for_HP) isn't needed. >>> >>> In fact, the patch is so easy that I am including it below. Please >>> test this (without either of your patches) to see if it works. >>> >>> Alan Stern >>> >>> >>> >>> >>> Index: usb-3.9/drivers/usb/host/uhci-hub.c >>> =================================================================== >>> --- usb-3.9.orig/drivers/usb/host/uhci-hub.c >>> +++ usb-3.9/drivers/usb/host/uhci-hub.c >>> @@ -225,7 +225,8 @@ static int uhci_hub_status_data(struct u >>> /* auto-stop if nothing connected for 1 second */ >>> if (any_ports_active(uhci)) >>> uhci->rh_state = UHCI_RH_RUNNING; >>> - else if (time_after_eq(jiffies, uhci->auto_stop_time)) >>> + else if (time_after_eq(jiffies, uhci->auto_stop_time) && >>> + !uhci->wait_for_hp) >>> suspend_rh(uhci, UHCI_RH_AUTO_STOPPED); >>> break; >>> >>> >> I have tested the UHCI_RH_RUNNING_NODEVS case yeasterday, and it works. >> But the function suspend_rh is also called in other places, so I think >> it only fixes >> the warning when auto stop is called, but not fix the warning when >> uhci's bus_suspend >> is called, it will come out again. > Have you tried this? I expect the warning will not occur when the > bus_suspend routine is called, because then there will be a 1-ms delay, > not just a 400-us delay. I tested this, and the warning is gone. Is this patch committed ? I need to paste the link to suse bugzilla. > >> And if you add uhci->wait_for_hp check in the UHCI_RH_RUNNING_NODEVS case, >> all hp uhci devices will not auto stop, not only the virtual devices. I >> guess it may waste resource. > If you want, you can add a new flag specifically for virtual > controllers. But it shouldn't matter -- as long as your kernels are > built with CONFIG_PM_RUNTIME enabled, there won't be any significant > waste of resources. > > Alan Stern > I think we can check the product id to determine whether a device is virtual. Do you know if there is another way to check this? Thanks Zhen-Hua -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/