Setting modes (again) and operation cancellation

[Enrico Mioso]

Hello guys!!

After some time, I am playing again with modes setting.

Maybe it's absolutely normal, bt I am facing a situation where mode changes don't take effect apparently. Or, put another way:

root at OpenWrt:~# mmcli -m 0 --set-allowed-modes="any" --set-preferred-mode="none"
successfully set current modes in the modem
root at OpenWrt:~# mmcli -m 0 |grep -i "current: allowed"
            |              current: allowed: 2g, 3g, 4g; preferred: 4g
root at OpenWrt:~#

and mo matter, I am not able to set the preference to none.
Is this due to modem firmware not supporting this?
manufacturer: QUALCOMM INCORPORATED
model: QUECTEL Mobile Broadband Module
Firmware revision: EC25EFAR02A08M4G
Carrier config: default
h/w revision: 10000

Modes list:
supported: allowed: 2g; preferred: none
            allowed: 3g; preferred: none
            allowed: 4g; preferred: none
            allowed: 2g, 3g; preferred: 3g
            allowed: 2g, 3g; preferred: 2g
            allowed: 2g, 4g; preferred: 4g
            allowed: 2g, 4g; preferred: 2g
            allowed: 3g, 4g; preferred: 3g
            allowed: 3g, 4g; preferred: 4g
            allowed: 2g, 3g, 4g; preferred: 4g
            allowed: 2g, 3g, 4g; preferred: 3g
            allowed: 2g, 3g, 4g; preferred: 2g
current: allowed: 2g, 3g, 4g; preferred: 4g

Secondly: in our application we perform a fair amount of async calls. In exceptional cases where we care about order and operation completion, we do sync calls, but in most cases we use async operations.
I am clearly facing the issue of the program segfaulting sometimes when some operations are still pending at exit. I imagine I should use a GCancellable for that.
Could you give me any direction? Since I don't know at any given moments how many async operations are in progress.
Thank you very very much to all of you reading this message.

Enrico