Auto driver current?
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I may have imagined this but I though I watched a video where Thomas Sanladerer said that these TMC drivers could auto tune their current so that when they detected they were about to stall, the current would increase. Also, if they detect a skip, they would self correct their position.
Are these features implemented or have a been drinking too much eggnog?
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It's not quite that. The drivers have two features relevant to this discussion:
1. They can measure the back emf, which means that if you set them up correctly you can detect an approaching or actual stall within a certain speed range. This feature is called StallGuard2. See https://duet3d.com/wiki/Stall_detection_and_sensorless_homing for how RRF 1.20 uses it.
2. They have a facility that allows the current to be automatically reduced when they are not close to stalling. This feature is called coolStep. You can enable it using the same M915 command that is used to configure the stall sensitivity.
Either way, the motors need to be chosen carefully to support these features well. High inductance low current motors are almost certainly best because they generate a higher back emf - but these are exactly the types of motors you do not want to use if you want high movement speeds.
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Ok so maybe it's not the silver bullet that Tom painted it as
