[PATCH] Add DEVICE_OPEN_FLAG_DATA_FORMAT

[Marcel Holtmann]

Hi Bjorn,

> > Some devices (like Sierra's MC7700 w/the latest AT&T firmware), default
> > to a packet data format that's incompatable with qmi_wwan/usbnet.  This results
> > in us being unable to get a DHCP address or otherwise use the virtual ethernet
> > port.  Add DEVICE_OPEN_FLAG_DATA_FORMAT to set the data format
> > to default (no-QoS) and data mode to ethernet when opening.
> 
> Explicitly setting the expected mode seems to be wise in any case.
> 
> But I am curious: What is the new default?  Raw IP and no QoS? Did
> anyone find any use for the QoS mode, BTW?
> 
> I am asking because it seems we have to add some data interception hooks
> to cdc_wdm to support MBIM, and I am playing with the idea to let the
> qmi_wwan snoop on "Set Data Format" messages and just support whatever
> mode you set.  It can most certainly be done, and it won't be much code
> either.

instead of doing some magic snooping, I would prefer that we add some
ioctl that allows us to list supported modes and allow them to change.
So userspace can make the call here. And not the kernel doing some magic
behind the scenes.

Regards

Marcel