USB Stack

The USB stack is the component which provides the communication between USB devices and their respective drivers and applications. It consists of multiple files, each with a distinct function. The USB stack in ReactOS is currently limited. This page documents the development of the new USB stack. Development work on a USB 3 stack is in progress.

NOTE: There is a known issue with booting ReactOS from the internal HDD with a USB storage device connected which causes ROS to lose the boot device. Until this problem is fixed or a workaround is developed, please unplug any USB storage devices during boot!

Overview

The goal is to develop a USB stack which:

• is USB 1.1 - 2.0 compliant
• uses WDM (NT 5) API
• is compatible with all USB devices and drivers (which adhere to the standard)

The entire stack will be fully documented and the implementation progress detailed on this page.

Goals

• Primary Goal: USBHID (human input devices) and storage functionality working (Alpha).
• Secondary Goal: Audio and other support added.
• Beyond: testing and debugging.

Due to the complexity and size, no release dates will be provided as of now.

Status

USB Core Status

• There are 2 USB specifications for the USB 1.1 standard. Devices which are used in this standard are mice, keyboards, etc.
  • OHCI (Open Host Controller Interface Standard) - All transfers types are implemented (bulk, iso, control, interrupt)
  • UHCI (Universal Host Controller Interface Standard) - Totally missing. Though it should be do-able to use ohci driver as a base and use Haiku driver
• EHCI (Enhanced Host Controller Interface) - Implemented transfer types: bulk & control. Interrupt & Isochronous transfers are not implemented. Due to the missing transfer types, devices who utilize those transfer types will not be available.
• USBHUB - driver for managing port and hubs - Implementation state is unknown - michel martin has more information on that

USB Mass Storage Support Status

USB Mass Storage is implemented in USBSTOR driver and is fully working. Tested in WinXP + USBEHCI + USBSTOR. Mass storage support requires bulk and control transfers, which are implemented in USBEHCI].

HID Status

The HID framework is built on 5 drivers

• HIDUSB - this is the interface driver for the USB bus. Currently supported devices are mice. Basic keyboard support should also work currently.
• HIDCLASS - this is the class driver for HIDUSB and others. Functionality for mice & keyboard is implemented, though support for sending output reports is not implemented.
• MOUHID - mouse function driver for USB hid standard - Fully implemented and working.
• KBDHID - keyboard function driver for the hid standard - 90% implemented, needs KbdHid_InsertScanCodes implemented for keyboard scan code dispatching to kbdclass and led status indicator support (which requires sending output reports).
• HIDPARSE - driver for parsing report descriptors - functionality implemented for mice, keyboard support needs HidParser_TranslateUsage fully implemented for modifier state (caps lock, num lock, scroll lock).

What works and not

• Mouse support has been tested in WinXP with ReactOS USBOHCI + HIDUSB + HIDCLASS + MOUHID + HIDPARSE and is working. The USB + HID stack also works in ReactOS.
• Basic Keyboard support need a 2/3 functions implemented (coming soon).
• USB Mass storage support - Needs mountmgr / partmgr driver implemented. Will also need mountvol and other missing PnP stuff. Update: http://img687.imageshack.us/img687/3223/rosUSB2.png

- needs a few more issues to be resolved

See Also

• Supported USB Devices

• USB Todo List

References

• USB.org specifications
• XEN PV USB Drivers
• Roadmap for Developing USB Drivers
• Windows Driver Kit (Driver Development Kit)
• USB Driver Stack for Windows XP and later
• USB Device Stack for Windows XP and later
• USB 3.0 xHCI specifications