Re: Quectel EC21 with internal GSM MUX

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On Thu, 2025-09-25 at 14:55 +0000, Christian Meusel wrote:

<snip>

> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:48 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/plugins/quectel.c:ate_cb()
> 0x4f6400
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:48 target ofonod[4030]: at_chat_send_comm=
on:
> enqueued "AT+CMUX=3D0,0,5,127,10,3,30,10,2", len is 1
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:48 target ofonod[4030]: UART: >
> AT+CMUX=3D0,0,5,127,10,3,30,10,2\r
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:48 target ofonod[4030]: UART: < \r\n
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:48 target ofonod[4030]: UART: < OK\r\n
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:48 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/plugins/quectel.c:cmux_cb()
> 0x4f6400
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/src/modem.c:get_modem_prope
> rty() modem 0x4f6400 property Mux
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/plugins/quectel.c:cmux_acti
> vation_delay_cb() 0x4f6400
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/plugins/quectel.c:cmux_gatm
> ux() 0x4f6400
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/plugins/quectel.c:create_ch
> at() 0x4f6400
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/plugins/quectel.c:create_ch
> at() 0x4f6400
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/plugins/quectel.c:identify_
> model() 0x4f6400
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]: at_chat_send_comm=
on:
> enqueued "AT+CGMM", len is 1
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]: Aux: > AT+CGMM\r
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]: Aux: <
> \r\nEC21\r\n\r\nOK\r\n
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/plugins/quectel.c:cgmm_cb()
> 0x4f6400 ok 1
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/plugins/quectel.c:cgmm_cb()
> 0x4f6400 model EC21
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]:
> ../../../../../../workspace/sources/ofono/plugins/quectel.c:setup_aux
> () 0x4f6400
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]: at_chat_send_comm=
on:
> enqueued "ATE0; &C0; +CMEE=3D1", len is 1
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]: at_chat_send_comm=
on:
> enqueued "AT+QURCCFG=3D"urcport","uart1"", len is 2
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]: at_chat_send_comm=
on:
> enqueued "AT+CFUN?", len is 3
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]: Aux: > ATE0; &C0;=
 +CMEE=3D1\r
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:49 target ofonod[4030]: Aux: < \r\nOK\r\n
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:54 target ofonod[4030]: Aux: < \r\nNORMAL=
 POWER
> DOWN\r\n
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:54 target ofonod[4030]: Modem: < \r\nPOWE=
RED
> DOWN\r\n
> =C2=A0=C2=A0=C2=A0 Sep 25 14:45:54 target ofonod[4030]: Aux: < \r\nPOWERE=
D DOWN\r\n

I think these "POWER" notification from the modem are the culprit. We
carry the attached patch in our setup to avoid those messages stalling
the AT parser.

I must admit that past me would have written a better commit message,
but here we are :/

With that said: Why does the modem choose to power down? Is
someone/something toggling the power-up GPIO to the modem?

// Martin

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