ModemManager 1.6.4 on Raspbian Stretch cannot acquire the 'org.freedesktop.ModemManager1' service name

[Valens D'Silva]

Thank you Aleksandr. I should have know to read the wiki first 😊

I now see that the port /dev/ttyAMA0 is not whitelisted.

I found a post from an old mailing list on identifying the kernel driver and whitelisting it using this



ACTION!="add|change|move", GOTO="mm_platform_device_whitelist_end"

SUBSYSTEM!="platform", GOTO="mm_platform_device_whitelist_end"

DRIVERS=="imx-uart", ENV{ID_MM_PLATFORM_DRIVER_PROBE}="1"

LABEL="mm_platform_device_whitelist_end"

Before I found all this info I created 2 udev rules for /dev/ttyAMA0 and the /devices/platform/soc/20201000.serial. I named them randomly

cat /etc/udev/rules.d/s7648-ttyama0.rules
ACTION=="add", KERNEL=="20201000.serial", ENV{ID_MM_PLATFORM_DRIVER_PROBE}="1"

cat /etc/udev/rules.d/ttyama0.rules
ACTION=="add|change|move", KERNEL=="ttyAMA0", ENV{ID_MM_TTY_FLOW_CONTROL}="rts-cts", ENV{ID_MM_TTY_BAUDRATE}="115200"

And lastly here is the output of udevadm

udevadm info --attribute-walk /dev/ttyAMA0

Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.

  looking at device '/devices/platform/soc/20201000.serial/tty/ttyAMA0':
    KERNEL=="ttyAMA0"
    SUBSYSTEM=="tty"
    DRIVER==""

  looking at parent device '/devices/platform/soc/20201000.serial':
    KERNELS=="20201000.serial"
    SUBSYSTEMS=="amba"
    DRIVERS=="uart-pl011"
    ATTRS{driver_override}=="(null)"
    ATTRS{id}=="00241011"
    ATTRS{irq0}=="81"

  looking at parent device '/devices/platform/soc':
    KERNELS=="soc"
    SUBSYSTEMS=="platform"
    DRIVERS==""
    ATTRS{driver_override}=="(null)"

  looking at parent device '/devices/platform':
    KERNELS=="platform"
    SUBSYSTEMS==""
    DRIVERS==""

I think to get my port whitelisted I should just create:
platform-uart-pl0111.rules  in /etc/udev/rules.d



with



ACTION!="add|change|move", GOTO="mm_platform_device_whitelist_end"

SUBSYSTEM!="platform", GOTO="mm_platform_device_whitelist_end"

DRIVERS=="uart-pl011", ENV{ID_MM_PLATFORM_DRIVER_PROBE}="1"

LABEL="mm_platform_device_whitelist_end"

Is that correct?
Thanks,

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

From: Aleksander Morgado<mailto:aleksander at aleksander.es>
Sent: Friday, April 3, 2020 11:10 AM
To: Valens D'Silva<mailto:valens.dsilva at revivalanalytics.com>
Cc: modemmanager-devel at lists.freedesktop.org<mailto:modemmanager-devel at lists.freedesktop.org>
Subject: Re: ModemManager 1.6.4 on Raspbian Stretch cannot acquire the 'org.freedesktop.ModemManager1' service name

Hey,

>
>
>
> I am trying to get a UART connected modem working with Modem Manager.
>
>
>
> When I run ModemManager in Debug I get this error
>
>
>
> Could not acquire the 'org.freedesktop.ModemManager1' service name
>
>


You need to stop the system-managed ModemManager before you run your
own instance in debug mode; try:

$ sudo systemctl stop ModemManager
$ sudo /usr/sbin/ModemManager --debug

See https://www.freedesktop.org/wiki/Software/ModemManager/Debugging/

--
Aleksander
https://aleksander.es

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