[RFC] Probing ttys by default

Aleksander Morgado aleksander at aleksander.es
Fri Mar 21 04:35:47 PDT 2014

On Fri, Mar 21, 2014 at 11:37 AM, Sven Köhler <sven.koehler at gmail.com> wrote:
> The kernel cdc_acm driver could expose whether the device seems to be a
> modem. It knows, through the bmCapabilities field in the CDC Call
> Management descriptor [1]. Another field that comes to mind is the
> bInterfaceProtocol of the Interface Descriptor. For devices that don't
> speak AT-commands it should be zero.
> Then one can craft some general udev rule that grey- or blacklists
> (what's the difference) all devices that don't seem to be a modem. If
> there devices out there that erroneously report that they don't have
> calling capabilities, then that those would have to be whitelisted.
> I can confirm that for the UMTS card in my Laptop, lsusb explicitly
> lists that it speaks the AT-commands protocol (bInterfaceProtocol=1) and
> that it has call management (bmCapabilities=3 in the CDC Call Management
> descriptor).

Bjørn, Dan, do you guys think that this is something doable? Or,
otherwise, do you have any other idea on how we can handle this


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