Clarify LCD_BED_LEVELING requirements

[fiveangle]

LCD_BED_LEVELING requires MBL or PROBE_MANUALLY with auto bed leveling enabled. See #7396

[thinkyhead]

I suppose that helps, but of course one cannot enable auto bed leveling at all without enabling either PROBE_MANUALLY or one of the other probes.

[fiveangle]

You're preaching to the choir. The trouble is user enables PROBE_MANUALLY and LCD_BED_LEVELING, thinks it should work, doesn't accept that it also requires ABL, and holds the SanityCheck.h error up as evidence. o_O

[Roxy-3D]

I suppose that helps, but of course one cannot enable auto bed leveling at all without enabling either PROBE_MANUALLY or one of the other probes.

Technically... That is not true. Because UBL has manual probing code built into its G29 P2 command....
Or alternatively... The user could just do a G29 P0 to zero the mesh... Then use G26 and G29 P4 to edit the mesh into a usable state....

But really.... The user should have a probe!

[fiveangle]

One could argue that UBL should be "fixed" to require PROBE_MANUALLY before enabling the feature then ;)

[Roxy-3D]

Well.... What we really need to do is ALWAYS allow a manual probe option. And allow that to be mixed with automated Z-Probing.... But that is very difficult to do without re-writing all the probe code.