Initial QMI commands with Huawei cards

[Marcel Holtmann]

Hello again,

> I am testing QMI on various Huawei cards and I have a problem when
> sending the first QMI command to early. It never gets answered.
> 
> Either we have to withhold the POLLOUT from the kernel until the device
> is really ready. Or it has to do with QMI_CTL_SYNC command/indication,
> but I have no idea what it is suppose to do. On the Gobi 2000 cards it
> is not even supported.

so I gave up on trying to figure out what QMI_CTL_SYNC indications
really mean. Since they have no relation to when the device is ready to
respond to commands.

Seems like the control endpoint is still initializing and thus no
responses are send. Could be similar to the problem that we saw with AT
command based modems and SIM initialization. It takes a little bit
before it is ready to use.

I get the feeling that every service sends out the QMI_CTL_SYNC, but
without knowing the service that send them or how many services there
are in total, this is fully useless as well.

In the end I just keep trying the modem for a little while and
re-sending the commands before giving up. That works pretty well for my
Huawei and Gobi 2000 based devices. And yes, the 2000 has the same
problem, even while the no-responding-time is shorter than with the
other cards. I suspect because it supports less services.

Anyway, I pushed all the code into the oFono GIT tree. It has support
for device information, SIM handling, network registration, SMS, data
connections and GPS. Works nicely on 2G/3G and also LTE.

I have also partial code for UIM and STK handling, but that is still
incomplete at this moment.

Regards

Marcel