@Otso @fcwilt @gloomyandy Thanks to this thread, I have updated various parts of the documentation:
G1 S parameter section is updated to include that max laser power is set by M452.
G1 S parameter range has been updated, which was 0..254, to 0-255.
G1 S parameter section now describes 'laser clustering', which was added in RRF 3.5.0-beta3.
M42 and M106, where the range of values for PWM and fan settings is referred to, is now worded as follows:
The S field may be in the range 0.0-1.0 or >1.0-255. 0 is off in both cases.
I investigated M3 and M5 support (M4 has never been supported) in laser mode. M3 and M5 are still supported in laser mode, but in 'non-sticky' mode (M452 S0), they are redundant, as all G1 commands need an S parameter to fire the laser, otherwise it just defaults to S0. In 'sticky' mode (M452 S1), you can set the laser with, for example, M3 S255, then subsequent G1 moves will use that setting without needing an S parameter. M5 effectively sets G1 S0. M3/M5 can't be used to fire the laser on their own; the laser will only fire with a G1 movement command.
I will update M3, M4, M5, M452 in the Gcode dictionary, and https://docs.duet3d.com/User_manual/Machine_configuration/Configuration_laser, with the above information.
Ian