EM7565 failing if host reboots whithout power cycling the modem

[Peter Naulls]

On 3/20/23 09:26, John Marrett wrote:
> Bjørn,
> 

> 
> You should either open a case with the modem manufacturer if you have some kind 
> of support agreement. If you don't then you could ask about it on the sierra 
> wireless forums ( https://forum.sierrawireless.com/ 
> <https://forum.sierrawireless.com/> ). This problem is likely to affect other 
> people and you have very detailed and clean information about the problem. 
> Sierra can raise it to the modem manufacturer.
> 
> Have you tried unloading xhci_pci before rebooting the system? This might help?
> 
>     We need a woraround for the host system.  But what?  Since I have adb
>     access, I can obviously just reboot the modem.  Which works.  But what
>     about the "normal" modem configuration?  Figure out a way to cut USB
>     port power?  I guess this is possible on that platform, although I don't
>     think it's implemented.  It's not a very generic solution, though.  But
>     maybe this isn't a very generic problem? 
> 

Yeah, I've only worked on a couple of modems, but from my colleagues, this
is pretty normal.

On my setup, we have to both power cycle the modem and also cycle the USB
hub to regain proper control. This latter step might be the key here - you
can use uhubctl.