[BUG] Enders 3 V2, Select Auto Bed Leveling on the controller will freeze the machine

[fleek]

Bug Description

Selecting the bed leveling option on the controller will freeze the machine if Autohome was not selected prior.

My Configurations

Marlin-bugfix-2.0.x-Ender3V2-BLTouchOn5Pin-18Jul2020.zip

Required: Please include a ZIP file containing your Configuration.h and Configuration_adv.h files.

Steps to Reproduce

Additional Information

G29 expects a prior G28. However, if the menu option for G29 was not chosen in sequence after a G28 (Autohome), it will freeze the machine.

To check if Autohome was being done and if not issue G28 command prior to G29.

[fleek]

I traced the function to dwin.cpp

`/* Leveling */

void HMI_Leveling(void) {
Popup_Window_Leveling();
DWIN_UpdateLCD();
queue.inject_P(PSTR("G29"));
}`

Currently it is only injecting G29, however, if there is no prior G28 being done, it will result in a hang of the machine.
Is there a way to check if G28 was performed before? Otherwise could a forceful G28 be injected prior to G29?

Sorry, I am not quite familiar with the marlin code, so I need to ask before I do something silly.

[CRCinAU]

@fleek - This is one of the patches I finalised last week but didn't get a chance to submit...

I suggest: G28 O\nG29\nM420 S1\n - otherwise the machine doesn't have a way to enable to grid to be used.

[fleek]

M420 S1 is to enable the use of the grid after a G28 because G28 disables the grid usage. However, when a G29 is issued, the grid usage is automatically enabled. G28 O\nG29\nM500 would be more appropriate as it will save the probed grid to EEPROM.

[github-actions]

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