[Bug] GPS does not show up for PixRacer Pro in v1.15.0

[sssagara]

Describe the bug

GPS module (Holybro Neo-M8N) doesn't seem to be recognized when PixRacer Pro is flashed to v1.15.0. GPS Status does not show up as valid in QGC main page and GPS_RAW_INT message is also not present in MAVLink Inspector.

When flashed with v1.14.3 with the exact same setup and params, GPS module is immediately recognized and GPS status and GPS_RAW_INT message are present.

To Reproduce

1. Flash PixRacer Pro to v1.15.0 (tried via both QGC firmware tab and building from source)
   
2. GPS status shows up as invalid on QGC main page
   
3. GPS_RAW_INT message not present in MAVLink Inspector
   
4. GPS still does not show up even when drone is placed outdoors with clear skies

Expected behavior

Expected to see GPS status on QGC main page and GPS_RAW_INT message in MAVLink Inspector

Screenshot / Media

No response

Flight Log

https://review.px4.io/plot_app?log=a0c84de9-c359-4f8c-b4b1-4331c02232ba

Software Version

HW arch: MRO_PIXRACERPRO
PX4 git-hash: 30e763b
PX4 version: Release 1.15.0 (17760511)
OS: NuttX
OS version: Release 11.0.0 (184549631)
OS git-hash: 5d74bc138955e6f010a38e0f87f34e9a9019aecc
Build datetime: Sep 23 2024 14:27:51
Build uri: localhost
Build variant: default
Toolchain: GNU GCC, 9.3.1 20200408 (release)
PX4GUID: 00060000000035363233313251020046001c
MCU: STM32H7[4|5]xxx, rev. V

Flight controller

mRo PixRacer Pro

Vehicle type

Multicopter

How are the different components wired up (including port information)

1. GPS module plugged into GPS port of PixRacer Pro
2. GPS_1_CONFIG set to GPS 1 (Also tried setting GPS_2_CONFIG to GPS 1 but no difference)
3. SER_GPS1_BAUD set to Auto

Additional context

When flashed with v1.14.4 with the setup and params unchanged and the same, the GPS module is immediately recognized after flashing. Tried figuring out if the GPS module was faulty by testing it with a Pixhawk 4. When Pixhawk 4 is flashed with either v1.14.4 or v1.15.0, the same GPS module is immediately recognized and GPS_RAW_INT messages present in MAVLink Inspector

v1.14.4 PixRacer Pro

[bresch]

Found that dmesg reports

Starting GPS Port on /dev/ttyS3
Conflicting config for /dev/ttyS3

This is apparently because SEP_PORT1_CFG is also set to GPS 1 by default so it conflicts with GPS_1_CONFIG.

Solution for you @sssagara is to set SEP_PORT1_CFG to "disabled" and reboot.

[DronecodeBot]

This issue has been mentioned on Discussion Forum for PX4, Pixhawk, QGroundControl, MAVSDK, MAVLink. There might be relevant details there:

https://discuss.px4.io/t/firmware-v1-15-stable-gps-not-detected-cube-orange-herelink/40854/4

[sssagara]

Found that dmesg reports

Starting GPS Port on /dev/ttyS3
Conflicting config for /dev/ttyS3

This is apparently because SEP_PORT1_CFG is also set to GPS 1 by default so it conflicts with GPS_1_CONFIG.

Solution for you @sssagara is to set SEP_PORT1_CFG to "disabled" and reboot.

Yes! That solved it! Thank you for the help and really appreciate the quick reply!