On Fri, 4 Mar 2016, Devon Ash wrote:
> Failing that, can you at least provide a usbmon trace showing what
> happens when you plug a device into one of the bad ports?
>
> usbmon trace:
>
> I'm unable to get anything from doing "cat 0u && cat 5u && cat 6u"
> (which are all of the offending devices locations)
Is CONFIG_USB_MON set? If it is set to M, have you loaded the usbmon
module?
> And also a
> dmesg log with USB debugging enabled?
>
> dmesg shows nothing. I htink I'm missing something - to enable USB
> debugging all that needs to be done is mount the debugfs right?
No, that's not enough. I don't remember how 3.19 does it, but with
more modern kernels you have to enable dynamic debugging by doing:
echo 'module usbcore =p' >/sys/kernel/debug/dynamic_debug/control
That's assuming CONFIG_DYNAMIC_DEBUG is set, which it should be in a
typical distribution kernel.
> Regarding Kernel 4.2.0-30-lowlatency,
>
> system-udevd is now giving me the outputs on boot:
>
> seq 1106 '/devices/pci0000:00/0000:00:1a.0/usb5 killed (same for usb6)
> reason being ; a timeout
>
> Then I start to get
>
> usb 5-1: device not accepting address 5, error -110
> usb usb5-port1; unable to enumerate USB device
>
> and the same for usb6.
>
> There is also:
>
> system-udevd: worker terminated by signal 9, and then the system waits
> for 2-5 minutes, finishing with a kernel hang and a stack trace "not
> tainted, blocked for more than 120 seconds"
Can you post the actual dmesg log?
> here is the output of:
>
> sudo mount -t usbfs none /proc/bus/usb
>
> mount: mounting none on /proc/bus/usb failed: no such file or directory
There no longer is any such thing as a usbfs filesystem. Instead
there are USB device nodes under /dev/bus/usb.
> cat /proc/bus/usb/devices: no such file or directory
>
> sudo mount -t debugfs none /sys/kernel/debug
>
> mount: muonting none on /sys/kernel/debug failed: Device or resource busy
Probably because it's already mounted there.
> As well, all usbmon outputs are returning me nothing when plugging
> in/out the broken USB ports that are in question
What is the full path of the files you are watching for usbmon? They
should be things like /sys/kernel/debug/usb/usbmon/5u -- which of
course won't exist unless debugfs is properly mounted and usbmon is
properly loaded.
Alan Stern
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