AT commands to a Sierra Wireless EM9291

tom

@groupo I haven't been able to send AT commands to that flavor of Sierra modem, I've done everything via. qmicli at this point.

There's a good chance that driver would enable it but I haven't dug any deeper into it at this point.

groupo

@tom thanks for getting back to me. My hesitation with installing it was messing up something you guys have put into place and having to reflash. Can you think of any easy gotchas before I go through with it?

tom

@groupo Nah doesn't sound like anything too sketchy. It's easy to re-flash the SDK if you do mess anything up and I can help you through that if you get stuck.

groupo

@tom Might you be able to help with the install? I have the drivers but I am a not very savvy with any software that isnt MATLAB.

the readme is very straightforward, but I am running into issues:

run 'make' to install driver binaries
run 'make install' and reboot to install them

The makefile script looks for /lib/modules($shell uname -r)/build... which does not exist. I can mkdir it but I still get make errors. I am not even sure where I should place the folder 'usb' that these drivers are in.

I can provide the actual make script and anything else you'd wanna see... just want to see if youre able to help before dumping it all haha

tom

@groupo Try this before building:

sudo ln -s /usr/src/header /lib/modules/$(uname -r)/build

groupo

@tom

Done but still get errors

voxl2:/$ sudo ln -s /usr/src/header/ /lib/modules/$(uname -r)/build 
voxl2:/$ cd usb
voxl2:/usb$ make
make -C /lib/modules/4.19.125/build M=/usb
make[1]: Entering directory '/lib/modules/4.19.125/build'
make[1]: *** No targets specified and no makefile found.  Stop.
make[1]: Leaving directory '/lib/modules/4.19.125/build'
Makefile:12: recipe for target 'all' failed

groupo

@tom I see this is running libqmi 1.22.0. The latest, 1.32.0, has a command for AT commands. Have you tried this new version internally? Could I upgrade mine?

tom

@groupo Ooh cool, we haven't tried that before. Looks like you should be able to try upgrading it via. apt. Feel free to try that and let me know if you have luck!

groupo

@tom just apt update libqmi ? Again sorry, but I am not very familiar with linux.

Another thing, I may have deleted the contents of /usr/src/header while trying to delete that symbolic link you had me make earlier. I swore there was stuff in /header, but I dont see anything in there now. I ran rm -r /lib/modules/###/build which I thought should not touch anything past the link itself. If there is supposed to be stuff in there, can I get it back without reflashing?

tom

@groupo I don't know of a way to get those files back without reflashing.

I just checked and it doesn't seem like there's a newer version available via. apt with the repos currently on there.

You may have to build and install it via. source

groupo

@tom I was just typing a msg up to relay apt isnt showing any of them available for updating. I will try to reflash.

I need to be able to connect to a private LTE network (MCC-MNC 001-01) which, as far as I have read, the EM9291 does not natively search for. I've read you can issue AT commands to tweak how the modem operates but am at a standstill trying to either install drivers to enumerate ttyUSB0 or update qmicli to the newest version so that I can issue AT commands that way. I think reflashing is necessary to get those files back and reestablish some ground truth with my drone. I should be able to go through those directions on my own. After that, are you able to assist me with either of the two avenues I discussed? I am grossly unfamiliar with the platform's architecture, but if I could get you on even a short call I think it would greatly accelerate this process for the two of us.

tom

@groupo I can't provide a ton of help as I haven't tried it myself but you should be able to build and install a newer version of libqmi by following the instructions from here:

https://modemmanager.org/docs/libqmi/building/building-autotools/

In terms of which AT commands are required to send I can't really help there, it may require reading through Sierra's AT command docs

groupo

@tom I am talking to a dev from Sierra Wireless who can help with the AT commands. there are some very useful forum posts there for connecting to 'test' LTE networks. I just need to send the AT commands to do so. I need your assistance in either installing that driver to enumerate the port or updating qmi. I will try to update qmi first, as that seems like the simpler approach. I need libqmi 1.34 which switched from GNU autotools to Meson. That means nothing to me, I will just follow the steps, more FYI

groupo

@tom need Meson to get newest libqmi. Tried installing that but ran into more errors, I hate feeling like I am asking to be spoonfed but I really could use some guided direction here - I am extremely out of my element

tom

@groupo You can install meson and ninja with

sudo apt install meson ninja-build

groupo

@tom I did that successfully, the error came with running the third line below

voxl2:/$ sudo apt install meson ninja-build
Reading package lists... Done
Building dependency tree       
Reading state information... Done
ninja-build is already the newest version (1.8.2-1).
meson is already the newest version (0.45.1-2ubuntu0.18.04.2).
0 upgraded, 0 newly installed, 0 to remove and 37 not upgraded.
voxl2:/$ cd libqmi
voxl2:/libqmi(main)$ meson setup build --prefix=/usr
The Meson build system
Version: 0.45.1
Source dir: /libqmi
Build dir: /libqmi/build
Build type: native build

meson.build:223:10: ERROR: lexer
test_env = {
          ^

A full log can be found at /libqmi/build/meson-logs/meson-log.txt

tom

@groupo Hmm meson isn't something I'm familiar with so I don't know how to debug that.

Do you know if the version of libqmi has to be newer than 1.30? Otherwise you could try the older way to build using make

groupo

@tom unfortunately, the ability to send AT commands via qmicli was introduced in 1.32. What about trying the drivers again? I goofed the symbolic linking earlier. I redid it and the make script gets farther, but still eventually fails.

How come PORT is initialized with certain modems in voxl-configure-modem but not with the em9291. It looks like you just set PORT to ttyUSB0 and echo to it to send AT commands. Can i not just add that into the em9291 logic flow?

tom

@groupo /dev/ttyUSB0 only enumerates if the driver recognizes the hardware of having said capability. In this case, the driver that controls that port doesn't recognize that modem hardware, likely the driver is from before that hardware existed.

In these cases we usually have to make custom tweaks to the linux kernel drivers in order to add the support for the hardware.

If you'd like to experiment with doing that you can, building custom kernels allows adding custom support for new or existing hardware.

You can read more about building a custom kernel here: https://docs.modalai.com/voxl2-kernel-build-guide/

groupo

@tom I will explore the kernel stuff.

Re updating qmicli, I need meson >= 0.53.0 which is not supported on drone's ubuntu version. Is upgrading to a newer ubuntu on the drone an option?