Land failsafe broken without GPS

[AuterionWrikeBot]

When flying without GPS and losing RC the vehicle goes into land mode (given that it has been configured that way).
But the vehicle never detects landing because something with the flight task is broken (see messages below).

┆Attachments: Image-2019-02-16 01-08-33.png

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

Closing as stale.

[julianoes]

@bresch is this still an issue?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. Thank you for your contributions.

[julianoes]

Closing because there was no follow up.

[julianoes]

On a second read, let me reconsider this and check it.

[julianoes]

I can reproduce this in SITL using gpssim stop and then disconnecting the joystick in QGC:

WARN  [commander] Manual control lost
WARN  [commander] Failsafe enabled: no RC
WARN  [mc_pos_control] Auto activation failed with error: Activation Failed
WARN  [mc_pos_control] Position-Ctrl activation failed with error: Activation Failed
WARN  [mc_pos_control] Previous flight task failed, switching to mode 1
WARN  [mc_pos_control] Auto activation failed with error: Activation Failed
WARN  [mc_pos_control] Position-Ctrl activation failed with error: Activation Failed
WARN  [mc_pos_control] Position-Control Setpoint-Update failed
WARN  [mc_pos_control] Position-Control Setpoint-Update failed
WARN  [mc_pos_control] Position-Control Setpoint-Update failed
WARN  [mc_pos_control] Position-Control Setpoint-Update failed
WARN  [mc_pos_control] Position-Control Setpoint-Update failed
WARN  [mc_pos_control] Position-Control Setpoint-Update failed
WARN  [mc_pos_control] Position-Control Setpoint-Update failed
WARN  [mc_pos_control] Position-Control Setpoint-Update failed
WARN  [mc_pos_control] Position-Control Setpoint-Update failed
WARN  [mc_pos_control] Position-Control Setpoint-Update failed

It looks like the problem is that it goes into Land instead of Descend mode. Land mode requires a valid position while descend should only require a baro.

FYI @MaEtUgR

[julianoes]

NAVIGATION_STATE_DESCEND is mapped to the land functionality in navigator:
https://github.com/PX4/Firmware/blob/f9a5c91f8cc5f74ce8d2a0425f7b76d7af65a0a8/src/modules/navigator/navigator_main.cpp#L594-L597