[BUG] SMOOTH_LIN_ADVANCE stops my printer from extruding

[Carontes]

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

I had Marlin bugfix-2.1.x 2025-02-04 on my printer so I've decided to update it and I've flashed the latest bugfix at that time 2025-12-25. Everything was working good, change/load/unload was working, but when I tried to print nothing came out of the nozzle. I thought it was a hardware problem so I checked everything on my printer but nothing worked, so I realized it was a software problem. After some trials I discovered that the problem was given by the not commented line #define SMOOTH_LIN_ADVANCE, I tried to insert back the // at the beggining of the line and the printer worked again as it was supposed to do. Maybe it's the value after ADVANCE_TAU that doesn't make my printer to print but I don't know if that's the case

Bug Timeline

This bug started since the first time this feature has being adopted in the main code

Expected behavior

The printer should print whether #define SMOOTH_LIN_ADVANCE is enabled or not

Actual behavior

The printer doesn't print when #define SMOOTH_LIN_ADVANCE is enabled

Steps to Reproduce

No response

Version of Marlin Firmware

Marlin bugfix-2.1.x 2025-12-25

Printer model

No response

Electronics

No response

LCD/Controller

No response

Other add-ons

No response

Bed Leveling

ABL Bilinear mesh

Your Slicer

Cura

Host Software

None

Don't forget to include

• A ZIP file containing your Configuration.h and Configuration_adv.h.

Additional information & file uploads

conf.zip