EM7565 failing if host reboots whithout power cycling the modem

[Bjørn Mork]

Aleksander Morgado <aleksandermj at chromium.org> writes:

> Are we sure this is not an issue in the xhci driver itself? Maybe the
> specific combination of modem and xhci controller triggers some corner
> case that is not fully implemented correctly in xhci?
> Last time I found something similar it took me 2 weeks of reading the
> USB standard to come up with the fix
> (45ba2154d12fc43b70312198ec47085f10be801a).

Thanks for the pointer.  Impressive detective work there.  But you
should know that I'm too lazy to do any hard work like that.

> Did you report this at the LKML already? Maybe they have some hints on
> how to best handle this.

No, I haven't.  You're right.  This could very well be an issue with the
xhci host driver.  I was thinking that it might be related to the specific
quirks for this old and rather rare controller.  But it could very well
be a generic issue too, which just doesn't show up with other
implementations because theyr are more forgiving or whatever.

I'll try linux-usb and Mathias next.


Bjørn