Rockchip USB "device descriptor read/64, error -71": Fix

Symptoms

dmesg repeats "device descriptor read/64, error -71"
Device enumerates intermittently or not at all

Common causes

Insufficient or noisy VBUS (weak regulator, long cable, bus-powered hub)
USB 2.0 PHY tuning or wrong PHY node for the port
Damaged cable or connector, poor D+/D- routing on custom boards
Device needs more current than the port supplies

How to fix it

Watch enumeration live
```
sudo dmesg -w
lsusb -t
```
Rule out power and cabling
Try a powered hub and a short cable, and measure VBUS under load (it should stay above ~4.75 V).
Check the port's PHY and VBUS regulator in the DTS
Enable the matching u2phy host/otg node and reference the VBUS regulator via phy-supply.

Go deeper

Rockchip USB Device Not Detected: Host, OTG, VBUS and PHY Checklist

FAQ

What does "usb 1-1: device descriptor read/64, error -71" mean?

The host saw a device connect but could not read its descriptor. -71 is EPROTO, a USB protocol/signal error, usually caused by power, cabling or PHY configuration.

What causes "usb 1-1: device descriptor read/64, error -71"?

Insufficient or noisy VBUS (weak regulator, long cable, bus-powered hub); USB 2.0 PHY tuning or wrong PHY node for the port; Damaged cable or connector, poor D+/D- routing on custom boards; Device needs more current than the port supplies.

How do I fix "usb 1-1: device descriptor read/64, error -71"?

1. Watch enumeration live 2. Rule out power and cabling: Try a powered hub and a short cable, and measure VBUS under load (it should stay above ~4.75 V). 3. Check the port's PHY and VBUS regulator in the DTS: Enable the matching u2phy host/otg node and reference the VBUS regulator via phy-supply.