: Many Linux distributions come pre-installed with BRLTTY, a background process for braille display support. BRLTTY often misidentifies the CH340 chip as a braille device and "claims" the port, preventing serial tools like the Arduino IDE from accessing it.
The next time you plug in that $5 Arduino Nano clone and dmesg cheerfully reports ch341-uart converter now attached to ttyUSB0 , take a moment to appreciate the layers of kernel engineering that made it work. The CH340 driver isn’t glamorous. But it gets the job done—quietly, reliably, and without complaint. linux ch340 driver