lkml.org 
[lkml]   [2021]   [Jun]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Strange problem with USB device
On Tue, Jun 08, 2021 at 01:37:07PM -0500, Larry Finger wrote:
> On 6/8/21 1:20 PM, Alan Stern wrote:
> > One thing you might try is to turn on USB debugging before
> > plugging in the device:
> >
> > echo 'module usbcore =p' >/sys/kernel/debug/dynamic_debug/control
> >
> > The additional information this adds to the dmesg log may be
> > helpful.
>
> The BT device is part of the same card as the PCIe wifi device, thus
> there is no "plugging" it in a conventional sense.

I don't get it. If this is a PCIe device, why should it appear
on a USB bus? Wouldn't you expect it to show up as a PCI device
on a PCI bus instead?

> Is there some way to
> add the usbcore debugging statement to the kernel options line at boot
> time?

Yes. Use the kernel boot-line parameter:

usbcore.dyndbg="=p"

FYI, how to use dynamic debugging is explained at length in the
kernel source file
Documentation/admin-guide/dynamic-debug-howto.rst.

Alan Stern

> As I told GregKH, I am having the person with the problem try a rescue
> system with a 5.12 kernel.
>
> Larry
>

\
 
 \ /
  Last update: 2021-06-08 21:02    [W:0.075 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site