Re: [PATCH] qmi_wwan/cdc_ether: add device IDs for Dell 5804 (Novatel E371) WWAN card

On Wed, 2013-05-08 at 12:19 -0700, David Miller wrote:

From: dag dg <redacted>
Date: Wed, 8 May 2013 14:11:48 -0500

quoted

Just a side note on this. By default for this device, modprobe won't
load and assign the option driver. However, if cdc_ether is
blacklisted and you try to load option onto the device, it will try to
load the option driver onto where cdc_ether was being used, which will
cause the system to lock up. I'm not sure what needs to be done to
force qmi_wwan to take over cdc_ether without option grabbing these
IDs...

This is a consequence of "new_id" not being flexible enough to handle
class/subclass/protocol in addition to USB IDs.  Thus when you use it,
the driver binds to *all* USB interfaces, even ones that the driver
shouldn't ever control

So the issue you refer to is actually user error, helped by a
too-coarse-grained kernel API.  It's not an issue when things are all
done correctly, which is to say when the USB IDs and interface
class/subclass/protocol are properly added to the kernel drivers.

The option patch I posted earlier will fix this issue correctly.

Dan