embedded protocol_error ai_generated true

USB HID: endpoint 0x81 stalled, host reset required

ID: embedded/usb-hid-endpoint-stall

Also available as: JSON · Markdown · 中文
80%Fix Rate
87%Confidence
1Evidence
2024-07-08First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
USB HID v1.11 active — — —
STM32 USB Device Library v2.6.0 active — — —
TinyUSB v0.15.0 active — — —

Root Cause

USB HID endpoint stalled due to protocol violation (e.g., report size mismatch, invalid report ID, or host sending unsupported request).

generic

中文

USB HID端点因协议违规而停滞（例如，报告大小不匹配、无效的报告ID或主机发送不支持请求）。

Official Documentation

https://www.usb.org/document-library/device-class-definition-hid-111

Workarounds

  1. 85% success Verify HID report descriptor matches the actual report size sent. Use a USB analyzer (e.g., Wireshark with usbmon) to capture host requests and ensure firmware responds correctly. 
    Verify HID report descriptor matches the actual report size sent. Use a USB analyzer (e.g., Wireshark with usbmon) to capture host requests and ensure firmware responds correctly.
  2. 80% success Implement a callback to clear endpoint stall on host request (e.g., ClearFeature(ENDPOINT_HALT)). In STM32 USB stack, override USBD_HID_SetupStage. 
    Implement a callback to clear endpoint stall on host request (e.g., ClearFeature(ENDPOINT_HALT)). In STM32 USB stack, override USBD_HID_SetupStage.

中文步骤

  1. Verify HID report descriptor matches the actual report size sent. Use a USB analyzer (e.g., Wireshark with usbmon) to capture host requests and ensure firmware responds correctly.
  2. Implement a callback to clear endpoint stall on host request (e.g., ClearFeature(ENDPOINT_HALT)). In STM32 USB stack, override USBD_HID_SetupStage.

Dead Ends

Common approaches that don't work:

  1. Re-enumerate the device by power-cycling the USB cable 70% fail

    The stall condition persists because the firmware does not clear the endpoint halt condition; enumeration alone does not fix the logic error.

  2. Increase USB buffer size to accommodate larger reports 85% fail

    Stall is caused by protocol mismatch, not buffer overflow; larger buffers do not resolve incorrect report descriptors.

  3. Disable endpoint halt in firmware unconditionally 60% fail

    Forces data transfer but may cause host-side timeout or data corruption if the report format is still invalid.