Hi, 'Unknown symbol in module' happens after the actions below: rmmod ehci-hcd modprobe ehci-hcd kernel version: 2.6.35-rc6+gregkh tree+wireless tree dmsg info: [ 689.025428] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver [ 689.025431] Warning! ehci_hcd should always be loaded before uhci_hcd and ohci_hcd, not after [ 689.025434] ehci_hcd: block sizes: qh 104 qtd 96 itd 192 sitd 96 >From source code of ehci-hcd, seems debugfs_create_dir or usb_debug_root in ehci_hcd_init is thought as unknown symbol mistakenly by kernel. -- Lei Ming -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html