[review] New 'fibocom' plugin

[Reinhard Speyerer]

On Thu, Jul 19, 2018 at 09:44:57PM +0200, Aleksander Morgado wrote:
> On Thu, Jul 19, 2018 at 9:23 PM, Dan Williams <dcbw at redhat.com> wrote:
> > On Thu, 2018-07-19 at 21:10 +0200, Aleksander Morgado wrote:
> >> > On Chrome OS, we simply use ID_MM_PORT_IGNORE to ignore all AT
> >> > ports
> >> > on the L850-GL module (e.g.
> >> > https://chromium.googlesource.com/chromiumos/overlays/chromiumos-ov
> >> > erlay/+/master/net-misc/modemmanager-next/files/77-mm-fibocom-port-
> >> > types.rules).
> >> >
> >> > The modem is functional with just MBIM and supported via the
> >> > generic
> >> > plugin, which is the approach we took on Chrome OS. IMHO, there is
> >> > little added benefit with a new modem plugin. More importantly, AT
> >> > probing takes quite some time, and I observed it often took 7
> >> > seconds.
> >> > We've been trying hard for some time to move everything to purely
> >> > MBIM
> >> > or QMI :)
> >> >
> >>
> >> I'm going to extend this plugin in the following weeks with more
> >> features that will require the use of the AT port, e.g. GPS location
> >> and such. I agree that probing is a bit slow right now, but that is
> >> just because the DIAG port goes first through a series of AT probing
> >> steps which are not needed. For devices with fixed layouts like this
> >> one, adding udev tags to specify port types isn't bad IMO, and we
> >> should probably do that for the DIAG port (i.e. flag it as "not AT"
> >> for example).
> >
> > Agreed; ideally we can begin to restrict which ports we bother probing
> > for DIAG, since with QMI and MBIM DIAG is much less useful these days.
> >
> 
> You may know this better than me; are all DIAG ports from all qualcomm
> modems ever of the same class/subclass/protocol? i.e. Cls=ff(vend.)
> Sub=ff Prot=ff
> In other words, should we bother probing QCDM for ports that are not ff/ff/ff?

Hi Aleksander,

at least some Huawei mobiles like ME909u

    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass      1 
      bInterfaceProtocol     19 
      iInterface             51 HUAWEI Mobile Connect - Application Interface

and Cinterion PLS8 with firmware >= 02.x

    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        9
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass        10 CDC Data
      bInterfaceSubClass      0 Unused
      bInterfaceProtocol      0 
      iInterface              8 CDC ACM Data for DIAG

are exceptions to the rule.

Regards,
Reinhard