Re: [MM] [PATCH 2/5] novatel: Use the ALLOWED_SINGLE_AT property. Saves 5 seconds on probing.

[Bjørn Mork <bjorn mork no>]

Nathan Williams <njw google com> writes:
> On Wed, May 2, 2012 at 6:11 AM, Aleksander Morgado <aleksander lanedo com>wrote:
>
>> On 05/01/2012 06:07 PM, Nathan Williams wrote:
>> > Date: Thu, 22 Mar 2012 16:18:24 -0400
>> > Subject: [PATCH 2/5] novatel: Use the ALLOWED_SINGLE_AT property. Saves 5
>> >  seconds on probing.
>>
>> Is it that the modem exposes only one AT port? Or that it exposes
>> multiple ports but only one is needed? The property was meant for the
>> former case only, not for the latter.
>
>
> With this modem only one of the four exposed serial ports is an AT port. I
> believe the remaining ones are two Qualcomm things and GPS.

That sounds very likely.  A wild guess based on similar devices is that
the four ports are AT, QCDM, NMEA and QMI.  You could try writing
$GPS_START to the suspected NMEA port and see if that enables output
from the GPS.  QCDM could be tested using the tests in libqcdm (included
with ModemManager).

Testing for a QMI port is currenly non-trivial. You will have to modify
the cdc-wdm or qmi_wwan drivers to bind to the device and see if it
replies to QMI.  A nice test util for someone to write (I've been
planning to, but haven't had the time and probably won't either...)
would be something using libusb to send a CDC embedded QMI message (the
subsystem version check looks like a good candidate) to a given
device/interface.  Should be fairly easy to write.



Bjørn