limit GRID_MAX_POINTS_[XY] to 2-7 for MESH_BED_LEVELING

[ellensp]

Description

As requested in #27785
Updated sanity checks for GRID_MAX_POINTS_X and GRID_MAX_POINTS_Y when using MESH_BED_LEVELING

There was already an upper limit, but no lower limit.
The upper limit in Config says "Don't use more than 7 points per axis" so I reduced the upper limit to fit the description.

Requirements

MESH_BED_LEVELING + some sort of probe
change GRID_MAX_POINTS_X and or GRID_MAX_POINTS_Y

Benefits

User cannot exceed limits.

Related Issues

[BUG] Using one 'GRID_MAX_POINTS' per axis for MESH_BED_LEVELING leads to crash ride #27785

[thisiskeithb]

The upper limit in Config says "Don't use more than 7 points per axis" so I reduced the upper limit to fit the description.

Perhaps the description should have been updated instead 🙂

[classicrocker883]

I havent had any issues using 8 or 9 with MESH_BED_LEVELING. Ideally, for Bilinear and UBL I use 7. but that also depends on the probe offset, the bigger the X offset the more limited you can move the printhead to the right side of the bed. however this shouldn't matter using manual leveling because the "probe" is the nozzle, and grid points divide the bed up so all it gives is more points.

so perhaps the issue depends on the type of printer. I would take that into account.

[thinkyhead]

The comment on MBL mesh point limits was added by the original author in 2015 in f34b9c8 and the sanity check in 7dc64ef. Although changes were made to MBL extending the upper limit on points the comments and sanity checks were never changed.