Initialization timeout always generated when initialising the Quectel Lx6G GNSS modem

[j-delsol-dev]

Bug description
How does the zephyr chat modem work?
I use the Qectuel modem with interrupts enabled on the uart. The module starts up fine but goes into timeout during initialization even though I am receiving navigation data in the callbacks (latitude, longitude...).

To Reproduce
We use a custom baord with the gnss sample (zephyr/samples/drivers/gnss)
No compilation errors.

Expected behavior
I need to get the navigation data for my application. The gnss modem works. I have the navigation data vbut the initialization failed. I think that the drivers works but I don't understand the chat modem mechanism.

Impact
showstopper

Logs and console output

[00:00:00.000,000] <inf> quectel_lcx6g: Resuming
[00:00:00.000,000] <inf> quectel_lcx6g: Waiting until PM ready
[00:00:00.500,000] <dbg> modem_chat: modem_chat_script_start: running script: resume_script
[00:00:00.500,000] <dbg> modem_chat: modem_chat_script_next: resume_script: step: 0
[00:00:00.500,000] <dbg> modem_chat: modem_chat_script_next: sending: $PAIR002*38
$GPRMC,094620.000,V,,,,,0.23,178.94,051124,,,N,V*3F_received_command:  $PAIR002*38
[00:00:00.784,000] <dbg> modem_chat: modem_chat_script_next: resume_script: step: 1
[00:00:00.784,000] <dbg> modem_chat: modem_chat_script_next: sending: $PAIR062,0,1*3F
[00:00:00.825,000] <dbg> modem_chat: modem_chat_on_unknown_command_received: $GPVTG,178.94,T,,M,0.23,N,0.42,K,N*36
[00:00:00.867,000] <dbg> modem_chat: modem_chat_log_received_command: $GPGGA, 094620.000     0 0   M  M   41
[00:00:00.909,000] <dbg> modem_chat: modem_chat_on_unknown_command_received: $GPGSA,A,1,,,,,,,,,,,,,,,,1*03
[00:00:00.930,000] <dbg> modem_chat: modem_chat_on_unknown_command_received: $GPGSA,A,1,,,,,,,,,,,,,,,,2*00
[00:00:01.013,000] <dbg> modem_chat: modem_chat_log_received_command: $GPGSV, 2 1 08 30 68 163 25 07 60 072 13 11 46 236 18 33 36 200  0 6D
6 satellites reported (of which 4 tracked)!

... 

[00:00:09.352,000] <dbg> modem_chat: modem_chat_on_unknown_command_received: $GNGLL,4448.5379,N,00036.2412,W,094628.000,A,A*50
[00:00:09.394,000] <dbg> modem_chat: modem_chat_on_unknown_command_received: $GPTXT,01,01,02,ANTSTATUS=OPEN*2B
Got a fix!
8 satellites reported (of which 5 tracked)!
[00:00:09.826,000] <dbg> modem_chat: modem_chat_log_received_command: $GNRMC, 094629.000 A 4448.5409 N 00036.2398 W 1.11 177.11 051124   A V 1A
[00:00:09.868,000] <dbg> modem_chat: modem_chat_on_unknown_command_received: $GPVTG,177.11,T,,M,1.11,N,2.06,K,A*39
[00:00:09.952,000] <dbg> modem_chat: modem_chat_log_received_command: $GPGGA, 094629.000 4448.5409 N 00036.2398 W 1 5 2.55 -366.3 M 49.7 M   6F
gnss: gnss_info: {satellites_cnt: 5, hdop: 2.550, fix_status: GNSS_FIX, fix_quality: GNSS_SPS}
gnss: navigation_data: {latitude: 44.809014999, longitude : -0.603996666, bearing 177.110, speed 0.571, altitude: -366.300}
gnss: gnss_time: {hour: 9, minute: 46, millisecond 29000, month_day 5, month: 11, century_year: 24}
[00:00:09.993,000] <dbg> modem_chat: modem_chat_on_unknown_command_received: $GNGSA,A,3,06,11,30,,,,,,,,,,2.73,2.55,0.98,1*01
[00:00:10.056,000] <dbg> modem_chat: modem_chat_on_unknown_command_received: $GNGSA,A,3,73,86,,,,,,,,,,,2.73,2.55,0.98,2*0D
[00:00:10.119,000] <dbg> modem_chat: modem_chat_log_received_command: $GPGSV, 2 1 08 30 68 163 30 07 60 072  11 46 236 29 33 36 200  0 69
[00:00:10.181,000] <dbg> modem_chat: modem_chat_log_received_command: $GPGSV, 2 2 08 06 22 192 31 29 03 307  13   18 24   19 0 6A
gnss: gnss_satellite: {prn: 30, snr: 30, elevation 68, azimuth 163, system: G7 satellites reported (of which 4 tracked)!
PS, is_tracked: 1}
gnss: gnss_satellite: {prn: 7, snr: 0, elevation 60, azimuth 72, system: GPS, is_tracked: 0}
gnss: gnss_satellite: {prn: 11, snr: 29, elevation 46, azimuth 236, system: GPS, is_tracked: 1}
gnss: gnss_satellite: {prn: 120, snr: 0, elevation 36, azimuth 200, system: SBAS, is_tracked: 0}
gnss: gnss_satellite: {prn: 6, snr: 31, elevation 22, azimuth 192, system: GPS, is_tracked: 1}
gnss: gnss_satellite: {prn: 29, snr: 0, elevation 3, azimuth 307, system: GPS, is_tracked: 0}
gnss: gnss_satellite: {prn: 13, snr: 18, elevation 0, azimuth 0, system: GPS, is_tracked: 1}
gnss: gnss_satellite: {prn: 24, snr: 19, elevation 0, azimuth 0, system: GPS, is_tracked: 1}
[00:00:10.265,000] <dbg> modem_chat: modem_chat_log_received_command: $GLGSV, 2 1 07 71 63 356 30 73 44 128 47 70 38 076  86 28 238 30 1 73
[00:00:10.307,000] <dbg> modem_chat: modem_chat_log_received_command: $GLGSV, 2 2 07 83    88   28 81    1 77
gnss: gnss_satellite: {prn: 7, snr: 30, elevation 63, azimuth 356, system: GLONASS, is_tracked: 1}
gnss: gnss_satellite: {prn: 9, snr: 47, elevation 44, azimuth 128, system: GLONASS, is_tracked: 1}
gnss: gnss_satellite: {prn: 6, snr: 0, elevation 38, azimuth 76, system: GLONASS, is_tracked: 0}
gnss: gnss_satellite: {prn: 22, snr: 30, elevation 28, azimuth 238, system: GLONASS, is_tracked: 1}
gnss: gnss_satellite: {prn: 19, snr: 0, elevation 0, azimuth 0, system: GLONASS, is_tracked: 0}
gnss: gnss_satellite: {prn: 24, snr: 28, elevation 0, azimuth 0, system: GLONASS, is_tracked: 1}
gnss: gnss_satellite: {prn: 17, snr: 0, elevation 0, azimuth 0, system: GLONASS, is_tracked: 0}
[00:00:10.349,000] <dbg> modem_chat: modem_chat_on_unknown_command_received: $GNGLL,4448.5409,N,00036.2398,W,094629.000,A,A*54
[00:00:10.390,000] <dbg> modem_chat: modem_chat_on_unknown_command_received: $GPTXT,01,01,02,ANTSTATUS=OPEN*2B
[00:00:10.500,000] <wrn> modem_chat: resume_script: timed out
[00:00:10.500,000] <err> quectel_lcx6g: Failed to initialize GNSS

**Environment :**
- OS: Linux
 - Toolchain: Zephyr SDK (v3.7)

[henrikbrixandersen]

Please use our bug template when reporting bugs. You need to edit this issue to include the information requested in https://github.com/zephyrproject-rtos/zephyr/blob/main/.github/ISSUE_TEMPLATE/001_bug_report.md

[bjarki-andreasen]

Are you using a newer version of zephyr? there was a bug which caused timeouts due to utilizing spinlocks (which disable interrupts) for locking which was changed to semaphores, which could describe your issue :)

[bjarki-andreasen]

#72242 #72246

[j-delsol-dev]

Thank you.
I use Zephyr 3.7
In drivers, the semaphore is used (gnss_publish.c).

[j-delsol-dev]

The problem stems from the compatibility of the controls between the LCx6 and Lx6 series. We can't use the generic Quectel drivers with the Lx6 series.
Thank you for your support!

[bjarki-andreasen]

Ah, did not notice the LX :) quectel does have a habbit of using completely custom commands and between their modems :)