Re: [4.3] kworker busy in pm_runtime_work
From: Daniel J Blueman
Date: Sun Nov 22 2015 - 06:24:54 EST
On 16 November 2015 at 23:22, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Mon, 16 Nov 2015, Daniel J Blueman wrote:
>> Tuning USB suspend  in 4.3 on a Dell XPS 15 9553 (Skylake), I see a
>> kworker thread spinning in rpm_suspend .
>> What is the most useful debug to get here beyond the immediate ?
> 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
 is rfkill'd; the situation occurs even if I unload all related
What further debug would be useful?
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
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