Re: nm in different linux distributions - ppp versus qmi-wwan

[Bjørn Mork <bjorn mork no>]

Thomas Schäfer <tschaefer t-online de> writes:
> Am Freitag, 6. November 2015, 23:40:37 schrieben Sie:
>
> > This is obviously a misconfiguration of the option driver.  It could in
> > theory be patched, but I suspect some userspace script has been
> > "helpful", adding the device ID dynamically.  Could you post the output
> > of "cat /sys/bus/usb-serial/drivers/option1/new_id" as well?
>
>
> 12d1 1506 ff

Thanks.  That's your problem.  And it shows that Dan is correct: This is
very likely from usb_modeswitch.  I don't know of any other application
using the class filter.  The only problem is that filtering on the ff
(vendor specific) class isn't enough.  Both the serial functions and the
QMI function are vendor specific.

You can find the troublesome usb_modeswitch rule in (at least on my
Debian system) /lib/udev/rules.d/40-usb_modeswitch.rules:

# Adds the device ID to the "option" driver after a warm boot
# in cases when the device is yet unknown to the driver; checked
# against a list of known modems, or else no action
ATTR{bInterfaceClass}=="ff", ATTR{bInterfaceNumber}=="00", ATTRS{bNumConfigurations}=="*", 
RUN+="usb_modeswitch --driver-bind %p %s{idVendor} %s{idProduct} %E{PRODUCT}"


But as the comment says:  This shouldn't really touch any known modems.
Maybe your problem is with the usb_modeswitch database?

(FWIW, I have never really liked this feature, because it tends to
create hard-to-find bugs like the one you see, and because it prevents
necessary driver updates when it happens to work.  But it's not my call)



Bjørn