QMI CID leaks

[Teijo Kinnunen]

Hi.

On 9.4.2020 16.39, Aleksander Morgado wrote:

>> I'm working on a patch to detect M2M eUICC profile switches on Quectel
>> modems. Upon testing with Quectel EG25, which uses QMI, I noticed that
>> when MM reinitializes a modem (either due to hot-swap or MM restarting),
>> some of the QMI CIDs don't appear to be released. After ~10 times, the
>> modem detection fails due to QMI protocol error "ClientIdsExhausted".
>> The modem needs to be reset to recover from this.
>>
> 
> What ModemManager version are you using? Would you be able to confirm
> this issue with MM git master?

I was using the latest stable (1.12.8), just tested with master (though 
patched it a little to make it build with libqmi 1.24.6 which I've got 
installed in my system) - the same problem appears with it.

After investigating further, I suspect the problem could be in 
mm_port_qmi_close(); it should probably wait for 
qmi_device_release_client() completions before proceeding with closing 
the device.

I quickly also tested adding "sleep(2);" before qmi_device_close_async() 
call to give some time for releasing to complete and that seemed to fix it.

BR,

- Teijo