Unexpected +CGDCONT? error: 'Sending command failed: 'Resource temporarily unavailable''

[Ben Chan]

On Thu, Jul 20, 2017 at 1:42 AM, Ben Chan <benchan at chromium.org> wrote:
> Looking into it a bit more, the periodic signal update doesn't seem to
> cause the issue. But it seems like the primary port is closed and then
> reopened, and the init sequence runs while a connect operation is
> starting.
>

Looks like the problem is that, the data port is closed and reopened
during the disconnect operation. When the port is reopened, the init
AT sequence is sent via mm_port_serial_at_run_init_sequence, which
returns immediately without waiting for AT responses. The disconnect
operation completes but the init AT sequence may still be sending out.
A connect operation could happen right after the disconnect operation
completed but in the middle of an init sequence.