A poor power supply causes ripple voltage. When your JlSpp driver sees ripple, it misinterprets step pulses. The result: random layer shifts in prints or ruined PCBs.
Driver Name: jlspp
Version (Old): 1.2.3
Version (New): 1.3.0
Date: [Insert date]
Test Environment: [OS, hardware, kernel version] jlspp driver better
Do not use Windows Update. It will reinstall the generic version. A poor power supply causes ripple voltage
If this is a proprietary driver (e.g., for a custom USB device, printer, industrial controller, or legacy system), please provide: # Install benchmark tool sudo apt install parport-tools
# Install benchmark tool
sudo apt install parport-tools
sudo ppdev_test /dev/parport0 --mode epp --speed
Expected results:
| Symptom | Likely Cause | Fix | |---------|--------------|-----| | High CPU usage (90%+) | Polling instead of IRQ | Reinstall driver with IRQ enabled | | Data corruption at high speed | Cable too long / unshielded | Shorten to 1m, add ferrites | | Device not detected in ECP mode | Missing DMA channel | Set DMA=1 in BIOS | | "Driver better" message | Driver falling back to SPP | Force EPP in BIOS + driver config |
The most common mistake users make is leaving the driver on default reference voltage (Vref). This leads to either: