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!usbkd.usbchain

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The !usbkd.usbchain command displays a USB device chain starting at a specified PDO, and going back to the root hub.

!usbkd.usbchain PDO

Parameters

PDO
Address of the physical device object (PDO) of a device that is connected to a USB hub.

DLL

Usbkd.dll

Examples

Here is one way to find the address of the PDO of a USB device. First enter !usbkd.usb2tree.

 kd> !usbkd.usb2tree
...
2)!ehci_info ffffe00001ca11a0 !devobj ffffe00001ca1050 PCI: VendorId 8086 DeviceId 293c RevisionId 0002 
    RootHub !hub2_info ffffe000023201a0 !devstack ffffe00002320050
        Port 1: !port2_info ffffe000021bf000 
        Port 2: !port2_info ffffe000021bfb40 
        Port 3: !port2_info ffffe000021c0680 !devstack ffffe00007c882a0
...

In the preceding output, the address of the PDO is the argument of the suggested command !devstack ffffe00007c882a0. Pass the address of the PDO to !usbkd.usbchain.

0: kd> !usbkd.usbchain ffffe00007c882a0

usbchain
*****************************************************************************
HUB PDO ffffe00007c882a0 on port 3 !usbhubext ffffe00007c883f0 ArmedForWake = 0
VID Xxxx PID Xxxx REV 0100  Xxxx Corporation
    HUB #3 FDO ffffe00002320050 , !usbhubext ffffe000023201a0  HWC_ARM=0
    ROOT HUB PDO(ext) @ffffe0000213c1a0
        ROOT HUB FDO @ffffe00001ca1050, !usbhcdext ffffe00001ca11a0 PCI Vendor:Device:...

See also

USB 2.0 Debugger Extensions

Universal Serial Bus (USB) Drivers