Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751847AbbKVLYK (ORCPT ); Sun, 22 Nov 2015 06:24:10 -0500 Received: from mail-oi0-f51.google.com ([209.85.218.51]:34215 "EHLO mail-oi0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751271AbbKVLYI (ORCPT ); Sun, 22 Nov 2015 06:24:08 -0500 MIME-Version: 1.0 X-Originating-IP: [175.156.160.103] In-Reply-To: References: Date: Sun, 22 Nov 2015 19:24:07 +0800 Message-ID: Subject: Re: [4.3] kworker busy in pm_runtime_work From: Daniel J Blueman To: linux-usb@vger.kernel.org, Linux Kernel Cc: Alan Stern Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1668 Lines: 46 On 16 November 2015 at 23:22, Alan Stern wrote: > On Mon, 16 Nov 2015, Daniel J Blueman wrote: > >> Tuning USB suspend [1] in 4.3 on a Dell XPS 15 9553 (Skylake), I see a >> kworker thread spinning in rpm_suspend [2]. >> >> What is the most useful debug to get here beyond the immediate [3]? > > You can try doing: > > echo 'module usbcore =p' >/sys/kernel/debug/dynamic_debug/control kworker and ksoftirqd spinning occurs when I echo 'auto' to all the USB control entries. Using Alan's excellent tip, we see this being logged repeatedly at a high rate: [ 353.245180] usb usb1-port4: status 0107 change 0000 [ 353.245194] usb usb1-port12: status 0507 change 0000 [ 353.245202] hub 1-0:1.0: state 7 ports 16 chg 0000 evt 0000 [ 353.245203] hub 1-0:1.0: hub_suspend [ 353.245205] usb usb1: bus auto-suspend, wakeup 1 [ 353.245206] usb usb1: bus suspend fail, err -16 [ 353.245207] hub 1-0:1.0: hub_resume ... So, EBUSY. Both the webcam is not open, and the bluetooth interface [1] is rfkill'd; the situation occurs even if I unload all related modules. What further debug would be useful? Thanks! Daniel -- [1] Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 002: ID 0a5c:6410 Broadcom Corp. Bus 001 Device 003: ID 1bcf:2b95 Sunplus Innovation Technology Inc. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub -- Daniel J Blueman -- 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/