The !usbkd.usbhcdlog command displays a portion of the debug log for a USB host controller.

!usbkd.usbhcdlog DeviceExtension[, NumberOfEntries]


Address of the device extension for the functional device object (FDO) of a UHCI or EHCI USB host controller.

The number of log entries to display. To display the entire log, set this parameter to -1.




Here is one way to find the address of the device extension for the FDO of a USB host controller. First enter !usbkd.usb2tree.

0 kd> !usbkd.usb2tree

EHCI MINIPORT(s) dt usbport!_USBPORT_MINIPORT_DRIVER ffffe00001f48bd0

2)!ehci_info ffffe00001ca11a0 !devobj ffffe00001ca1050 PCI: VendorId 8086 DeviceId 293c RevisionId 0002 

In the preceding output, the address of the device extension of the FDO is displayed as the argument of the DML command !ehci_info ffffe00001ca11a0.

Now pass the address of the device extension to the !usbhcdlog command. In this example, the second argument limits the display to four log entries.

0: kd> !usbkd.usbhcdlog ffffe00001ca11a0, 4

LOG@: ffffe00001ca11b8 
>LOG mask = 3ff idx = fff68e95 (295)
*LOG: ffffe000020192a0  LOGSTART: ffffe00002014000 *LOGEND: ffffe0000201bfe0 # 4 
[ 000] ffffe000020192a0 xSt0 ffffe00001ca1b88 0000000000000006 0000000000000001 
[ 001] ffffe000020192c0 xnd8 ffffe00001ca1b88 ffffe00001ca1050 0000000000000000 
[ 002] ffffe000020192e0 xnd0 ffffe00001ca1b88 ffffe00001ca1050 0000000000000000 
[ 003] ffffe00002019300 gNX0 0000000000000000 0000000000000000 ffffe00001ca1b88 

See also

USB 2.0 Debugger Extensions

Universal Serial Bus (USB) Drivers

Send comments about this topic to Microsoft