Support for reading second GPS instance is broken

[priseborough]

Bug Report

The firmware at commit 19e706f is unable to read a second GPS receiver connected to the TELEM2 port of a pixracer after making the following modifications:

1. set SYS_COMPANION to zero
2. Modify rcS file to start the second GPS instance, eg priseborough@f273157

The following console output is generated when the GPS status is queried:

Both reeceivers are UBlox M8N units and both work when plugged into the GPS port. The TELEM2 port is able to connect to a modem under normal usage.

[priseborough]

I have repeated this test with a pixhawk cube and it is not possible to get a GPS to connect to any port other than the default GPS port. The test used this commit to prevent GPS or companion computer connections starting on boot:

priseborough@8f2faf1

On the pixracer I connected the GPS receiver to the TELEM2 port and attempted to start using' gps start -d /dev/ttyS2'

The driver cycled through a range of GPS protocols and baud rates attempting to connect.

Repeating this test using the GPS connected to the TELEM2 port on a pixhawk 'cube' and starting the GPS via 'gps start -d /dev/ttyS2' produced the same result. I was unable to find a port mapping that worked for the GPS2 port.

[bkueng]

This should fix it: #9019. Can you cross-test it?

[priseborough]

Fixed on my hardware TXS.

[Rickyg32]

Has this issue been fixed in a gold release of code. I have the latest official build on my pixracer and it doesn't see the second GPS so curious how to get it working.

[bkueng]

Not yet, just in the latest beta version.

[Rickyg32]

bkueng thanks man. any idea on timing. I am a month away from wanting to maiden this new build so its not a problem for me right now. But you know what its like,m you want to remove all the bugs as you encounter them before you put it in the air.

[bkueng]

Hard to say, but a month should be enough. Alternatively you can:

• use the latest beta, we're in a pretty stable state right now
• cherry-pick GPS: explicitly disable flow control #9019 to stable (lowest risk, if you need it right now)

[Rickyg32]

Thanks man. I can wait. I have lots to do and the reality is, even if I wanted to maiden tomorrow, missing a gps isn't a real issue. I can wait, I just appreciate your getting back to me. I truly appreciate it

[Rickyg32]

hows that new release coming