Re: RE: RE: USB: add check to detect host controller hardware removal

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2023-11-06 08:54:50 [+0000], Li, Meng wrote:

> This is not my original issue that I encountered.
> I agree that we should remove the device from sys interface firstly,
> and then do hot-plug action.
> My original issue was the calltrace on RT kernel if I remove the
> device from sys interface.
> # echo 1 > /sys/bus/pci/devices/0001:01:00.0/remove
> xhci_hcd 0001:01:00.0: remove, state 1
> usb usb2: USB disconnect, device number 1
> usb 2-4: USB disconnect, device number 2
> xhci_hcd 0001:01:00.0: USB bus 2 deregistered
> BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
> in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 765, name: sh

Right.

> and then I checked the commit log to get which commit introduced this issue.
> I found out the commit is 
> commit c548795abe0d3520b74e18f23ca0a0d72deddab9
> Author: Alan Stern <stern@rowland.harvard.edu>
> Date:   Wed Jun 9 17:34:27 2010 -0400
> 
>     USB: add check to detect host controller hardware removal
> 
> And then, Alan Stern told me the background of this issue. so, I
> started to do hotplug operation on my board to see what symptom on my
> nxp-ls1043/6 board.
> And then there were lots of discussion followed.

Okay. I somehow mapped it that you try to add this to xhci.
The suggested replacement should cover it. Better if we could get rid of
it ;)

> Thanks,
> Limeng

Sebastian