On Mon, Jul 16, 2012 at 12:28 AM, Bjørn Mork <[email protected]> wrote: > Aleksander Morgado <[email protected]> writes: > > >> I was wondering if there's any effort going on to support MBIM devices > >> on Linux? > >> > > > > No plans yet for ModemManager (see thread [1]). Is there any device > > out there which already supports that protocol? > > > > Cheers, > > > > [1] > > > https://mail.gnome.org/archives/networkmanager-list/2011-November/msg00352.html > > If I understand this correctly, MBIM devices will combine CDC NCM with a > MBIM control channel in the exact same way QMI devices combine CDC ECM > with a QMI control channel. That means that the driver support could be > done as simple as combining cdc_ncm with the cdc_wdm subdriver (either > in the existing cdc_ncm driver, or as a new separate driver reusing code > from cdc_ncm). > > If this was done, then we would have the MBIM control channel exported > to userspace as a /dev/cdc-wdmX device, exactly like qmi_wwan exports > its QMI control channel. Leaving MBIM control protocol implementation > for userspace make sense for the same reasons it made sense to leave QMI > implementation for userspace. Boy, am I happy Marcel and others > convinced me to do that :-) >
I was on the same line of thinking but wasn't aware of the QMI driver. Could you point out its location to me? > > Hmm, I see now "The only difference is that instead of transporting > Ethernet frames, MBIM transports raw IP data streams". So we definitely > need a new driver based on cdc_ncm. Exporting and reusing a bit of > cdc_ncm would probably make most sense. And it might also be necessary > to extend the cdc_wdm subdriver interface if the cdc_ncm driver need to > see the USB_CDC_NOTIFY_NETWORK_CONNECTION and USB_CDC_NOTIFY_SPEED_CHANGE > notifications, or if it needs to send any control messages after the > probe phase. Don't know if it does. Doesn't really look like it… > > All this should still be a piece of cake to stitch together. If there > had been any devices, that is. So, no, I don't know of any effort to > support MBIM on Linux. There just isn't any need for it yet. The basic > kernel driver support can be added in a few weeks if necessary. > > See also the reply from Torgny Johansson in the thread Aleksander refer > to, pointing to this press release: > > http://www.ericsson.com/news/111201_ericsson_to_phase_out_pc_modules_for_mobile_broadband_access_244188808_c > > I am guessing here, but the whole MBIM thing looks like it was driven by > Ericsson, and it might just not happen when they have put it on hold. > Qualcomm are likely to be happy with their current QMI approach. Not > sure what value they would see in replacing that with a new standardized > protocol, if they are going to be the only ones using the new protocol... > Others? Microsoft? Yes, I guess they could drive this if they decided > that MBIM is the "RNDIS of wwan devices". Maybe they will?? > > A question back to you, Greg: Why do you ask? I ask because I've been assigned to either come up with a MBIM driver or help with an existing effort. > Do you know of any > device? Or planned device? Where can I get one? :-) > I should be getting a dev board sometime in the next few weeks. I don't even know the manufacturer. Where can you get one? no idea. > > > > Bjørn > Thanks, Greg
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