PreArm : Param Storage Failed, Storage Healthy check?

Hyungsukoh · October 21, 2021, 7:08am

Hello all.
I have a question on a “PreArm Check”.

I’m using modified firmware based on Copter 4.0.7,
I added ROI function for my specific Gimbal CAM.
And then, when I send a ROI target to my drone via MAVLink, the drone failed to pass the prearm check.
There is an error message “PreArm : Param Storage Failed” on MP.
It only happened when I using ROI.

I found that the message is displayed by prearm check in AP_Arming.cpp, “system_checks” function.
In the function,
if “hal.storage->healthy()” returns false, the message should displayed.
I found the “hal.storage->healthy()” on Storage.h in AP_HAL library.
But the function healthy always returns true.

How can it possible that the “hal.storage->healthy()” returns false?

amilcarlucas · October 21, 2021, 10:20am

If you do not have an SDcard or the SDcard is damaged, it will give that error.

Hyungsukoh · October 21, 2021, 10:37pm

Thanks for your reply

But, I tried with 2 Pixhawk Orange.
The error just occurs when I send ROI target.
I also format sd card and change to other one

Hyungsukoh · October 22, 2021, 6:38am

The message line is this :

github.com

ArduPilot/ardupilot/blob/Copter-4.0.7/libraries/AP_Arming/AP_Arming.cpp#L702

    
      
          
          
    return true;
          }
          
          
/*
            check base system operations
           */
          bool AP_Arming::system_checks(bool report)
          {
              if (check_enabled(ARMING_CHECK_SYSTEM)) {
                  if (!hal.storage->healthy()) {
                      check_failed(ARMING_CHECK_SYSTEM, report, "Param storage failed");
                      return false;
                  }
          #if AP_TERRAIN_AVAILABLE
                  const AP_Terrain *terrain = AP_Terrain::get_singleton();
                  if ((terrain != nullptr) && terrain->init_failed()) {
                      check_failed(ARMING_CHECK_SYSTEM, report, "Terrain out of memory");
                      return false;
                  }
          #endif

And in the line, ‘if’ calling ‘hal.storage->healthy()’.
The function ‘healthy()’ is declared and defined in AP_HAL/Storage.h.

github.com

ArduPilot/ardupilot/blob/Copter-4.0.7/libraries/AP_HAL/Storage.h#L13

    
      
          #include <stdint.h>
          #include "AP_HAL_Namespace.h"
          
          
class AP_HAL::Storage {
          public:
              virtual void init() = 0;
              virtual bool erase();
              virtual void read_block(void *dst, uint16_t src, size_t n) = 0;
              virtual void write_block(uint16_t dst, const void* src, size_t n) = 0;
              virtual void _timer_tick(void) {};
              virtual bool healthy(void) { return true; }
          };

The function seems always return true, and there is no other virtual function named ‘healthy’ in AP_HAL library.