From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+willy=40w.ods.org@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S263832AbTJ1DAy (ORCPT <rfc822;willy@w.ods.org>);
	Mon, 27 Oct 2003 22:00:54 -0500
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263834AbTJ1DAy
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Mon, 27 Oct 2003 22:00:54 -0500
Received: from palrel10.hp.com ([156.153.255.245]:34230 "EHLO palrel10.hp.com")
	by vger.kernel.org with ESMTP id S263832AbTJ1DA2 (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Mon, 27 Oct 2003 22:00:28 -0500
Date: Mon, 27 Oct 2003 19:00:17 -0800
From: David Mosberger <davidm@napali.hpl.hp.com>
Message-Id: <200310280300.h9S30Hkw003073@napali.hpl.hp.com>
To: Greg KH <greg@kroah.com>
Cc: davidm@hpl.hp.com, vojtech@suse.cz, linux-usb-devel@lists.sourceforge.net,
       linux-kernel@vger.kernel.org
Subject: Re: serious 2.6 bug in USB subsystem?
In-Reply-To: <20031028013013.GA3991@kroah.com>
References: <200310272235.h9RMZ9x1000602@napali.hpl.hp.com>
	<20031028013013.GA3991@kroah.com>
X-Mailer: VM 7.07 under Emacs 21.2.1
Reply-To: davidm@hpl.hp.com
X-URL: http://www.hpl.hp.com/personal/David_Mosberger/
Sender: linux-kernel-owner@vger.kernel.org
X-Mailing-List: linux-kernel@vger.kernel.org

>>>>> On Mon, 27 Oct 2003 17:30:13 -0800, Greg KH <greg@kroah.com> said:

  Greg> On Mon, Oct 27, 2003 at 02:35:09PM -0800, David Mosberger
  Greg> wrote:

  >> One-line summary: plug-in your USB keyboard, see your machine
  >> die.

  Greg> Any chance to know where the machine dies?  Any oops you can
  Greg> help us out with?

On x86, there is no OOps, it just freezes.  On ia64, I get a nice MCA
and from that we can infer that a USB host controller read from
address 0xf0000000 caused the problem but since this is asynchronous
to the kernel's code path, the instruction pointer etc. in the MCA
state dump isn't terribly helpful.  Actually, just now I got a case
where the ia64 machine hung (it does this occasionally, instead of
MCAing).  In this case, I got similar "timeout" messages as on the x86
box and the backtrace looked like this:

Call Trace:
 [<a00000020004ea70>] hidinput_connect+0x150/0x2ce0 [hid]
 [<a00000020004ad30>] hid_probe+0x1290/0x1ac0 [hid]
 [<a000000100557f40>] usb_probe_interface+0x100/0x240
 [<a000000100388e40>] bus_match+0xc0/0x140
 [<a000000100389490>] driver_attach+0x110/0x1a0
 [<a000000100389600>] bus_add_driver+0xe0/0x200
 [<a00000010038a600>] driver_register+0xc0/0xe0
 [<a000000100556310>] usb_register+0x110/0x1c0
 [<a00000020005c0e0>] hid_init+0x60/0x100 [hid]
 [<a0000001000ca2c0>] sys_init_module+0x3c0/0x2d00
 [<a000000100014de0>] ia64_ret_from_syscall+0x0/0x20

The machine still responded to ping's but was otherwise unreachable.

  >> So, I have this non-name USB keyboard (with built-in 2-port USB
  >> hub) which reliably crashes 2.6.0-test{8,9} on both x86 and ia64.
  >> In retrospect, it's clear to me that the same keyboard also
  >> occasionally crashes 2.4 kernels, but there the problem appears
  >> more seldom.  Perhaps once in 10 reboots and once the machine is
  >> booted and the keyboard is running, it keeps on working.  The
  >> keyboard in question is a BTC 5141H.

  Greg> If you do not load the HID driver, and disable automatic
  Greg> loading of the hid driver (echo '/sbin/true' >
  Greg> /proc/sys/kernel/hotplug) and plug in the device, does it
  Greg> still crash?

No, if I only load the OHCI HCD, the kernel doesn't crash.

  Greg> If not, can you get us the output of /proc/bus/usb/devices and
  Greg> lsusb with the device plugged in?

Sure, they're attached.  Note: there are devices other than the BTC
keyboard connected, but I verified that the same problem occurs even
when the BTC keyboard is the only USB device plugged into the machine.

  Greg> If not, does then loading the hid driver cause the problem?

Yes, it's the loading of the hid driver that's triggering the crash.

	--david

<--- lsusb output --><--- lsusb output --><--- lsusb output -->

Bus 002 Device 004: ID 046e:5303 Behavior Tech. Computer 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 Interface
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x046e Behavior Tech. Computer
  idProduct          0x5303 
  bcdDevice            0.01
  iManufacturer           1 BTC
  iProduct                2 USB Hub Keyboard   
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           59
    bNumInterfaces          2
    bConfigurationValue     1
    iConfiguration          2
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Devices
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      1 Keyboard
      iInterface              2 USB Hub Keyboard   
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.00
          bCountryCode            0
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      65
	  Report Descriptor: (length is 65)
            Item(Global): Usage Page, data= [ 0x01 ] 1
                            Generic Desktop Controls
            Item(Local ): Usage, data= [ 0x06 ] 6
                            Keyboard
            Item(Main  ): Collection, data= [ 0x01 ] 1
                            Application
            Item(Global): Usage Page, data= [ 0x07 ] 7
                            Keyboard
            Item(Local ): Usage Minimum, data= [ 0xe0 ] 224
                            Control Left
            Item(Local ): Usage Maximum, data= [ 0xe7 ] 231
                            GUI Right
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0x01 ] 1
            Item(Global): Report Size, data= [ 0x01 ] 1
            Item(Global): Report Count, data= [ 0x08 ] 8
            Item(Main  ): Input, data= [ 0x02 ] 2
                            Data Variable Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Report Count, data= [ 0x01 ] 1
            Item(Global): Report Size, data= [ 0x08 ] 8
            Item(Main  ): Input, data= [ 0x01 ] 1
                            Constant Array Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Report Count, data= [ 0x05 ] 5
            Item(Global): Report Size, data= [ 0x01 ] 1
            Item(Global): Usage Page, data= [ 0x08 ] 8
                            LEDs
            Item(Local ): Usage Minimum, data= [ 0x01 ] 1
                            NumLock
            Item(Local ): Usage Maximum, data= [ 0x05 ] 5
                            Kana
            Item(Main  ): Output, data= [ 0x02 ] 2
                            Data Variable Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Report Count, data= [ 0x01 ] 1
            Item(Global): Report Size, data= [ 0x03 ] 3
            Item(Main  ): Output, data= [ 0x01 ] 1
                            Constant Array Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Report Count, data= [ 0x06 ] 6
            Item(Global): Report Size, data= [ 0x08 ] 8
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0xff 0x00 ] 255
            Item(Global): Usage Page, data= [ 0x07 ] 7
                            Keyboard
            Item(Local ): Usage Minimum, data= [ 0x00 ] 0
                            No Event
            Item(Local ): Usage Maximum, data= [ 0xff 0x00 ] 255
                            (null)
            Item(Main  ): Input, data= [ 0x00 ] 0
                            Data Array Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Main  ): End Collection, data=none
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               none
        wMaxPacketSize          8
        bInterval              10
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Devices
      bInterfaceSubClass      0 No Subclass
      bInterfaceProtocol      0 None
      iInterface              2 USB Hub Keyboard   
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.00
          bCountryCode            0
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      67
	  Report Descriptor: (length is 67)
            Item(Global): Usage Page, data= [ 0x01 ] 1
                            Generic Desktop Controls
            Item(Local ): Usage, data= [ 0x00 ] 0
                            Undefined
            Item(Main  ): Collection, data= [ 0x01 ] 1
                            Application
            Item(Global): Report ID, data= [ 0x01 ] 1
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0x01 ] 1
            Item(Global): Report Size, data= [ 0x01 ] 1
            Item(Global): Report Count, data= [ 0x08 ] 8
            Item(Main  ): Input, data= [ 0x01 ] 1
                            Constant Array Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Main  ): End Collection, data=none
            Item(Global): Usage Page, data= [ 0x01 ] 1
                            Generic Desktop Controls
            Item(Local ): Usage, data= [ 0x80 ] 128
                            System Control
            Item(Main  ): Collection, data= [ 0x01 ] 1
                            Application
            Item(Global): Report ID, data= [ 0x02 ] 2
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0x01 ] 1
            Item(Local ): Usage Minimum, data= [ 0x81 ] 129
                            System Power Down
            Item(Local ): Usage Maximum, data= [ 0x83 ] 131
                            System Wake Up
            Item(Global): Report Size, data= [ 0x01 ] 1
            Item(Global): Report Count, data= [ 0x03 ] 3
            Item(Main  ): Input, data= [ 0x06 ] 6
                            Data Variable Relative No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Report Size, data= [ 0x05 ] 5
            Item(Global): Report Count, data= [ 0x01 ] 1
            Item(Main  ): Input, data= [ 0x01 ] 1
                            Constant Array Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Main  ): End Collection, data=none
            Item(Global): Usage Page, data= [ 0x01 ] 1
                            Generic Desktop Controls
            Item(Local ): Usage, data= [ 0x00 ] 0
                            Undefined
            Item(Main  ): Collection, data= [ 0x01 ] 1
                            Application
            Item(Global): Report ID, data= [ 0x03 ] 3
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0x01 ] 1
            Item(Global): Report Size, data= [ 0x01 ] 1
            Item(Global): Report Count, data= [ 0x18 ] 24
            Item(Main  ): Input, data= [ 0x01 ] 1
                            Constant Array Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Main  ): End Collection, data=none
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               none
        wMaxPacketSize          4
        bInterval             255
  Language IDs: (length=4)
     0409 English(US)

Bus 002 Device 003: ID 050d:0119 Belkin Components 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 Interface
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x050d Belkin Components
  idProduct          0x0119 
  bcdDevice            1.20
  iManufacturer           1 Belkin Components
  iProduct                2 USB-PS2 Adapter 
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           59
    bNumInterfaces          2
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xa0
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Devices
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      1 Keyboard
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.00
          bCountryCode            0
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      63
	  Report Descriptor: (length is 63)
            Item(Global): Usage Page, data= [ 0x01 ] 1
                            Generic Desktop Controls
            Item(Local ): Usage, data= [ 0x06 ] 6
                            Keyboard
            Item(Main  ): Collection, data= [ 0x01 ] 1
                            Application
            Item(Global): Usage Page, data= [ 0x07 ] 7
                            Keyboard
            Item(Local ): Usage Minimum, data= [ 0xe0 ] 224
                            Control Left
            Item(Local ): Usage Maximum, data= [ 0xe7 ] 231
                            GUI Right
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0x01 ] 1
            Item(Global): Report Count, data= [ 0x08 ] 8
            Item(Global): Report Size, data= [ 0x01 ] 1
            Item(Main  ): Input, data= [ 0x02 ] 2
                            Data Variable Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Report Count, data= [ 0x01 ] 1
            Item(Global): Report Size, data= [ 0x08 ] 8
            Item(Main  ): Input, data= [ 0x01 ] 1
                            Constant Array Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Report Count, data= [ 0x05 ] 5
            Item(Global): Report Size, data= [ 0x01 ] 1
            Item(Global): Usage Page, data= [ 0x08 ] 8
                            LEDs
            Item(Local ): Usage Minimum, data= [ 0x01 ] 1
                            NumLock
            Item(Local ): Usage Maximum, data= [ 0x05 ] 5
                            Kana
            Item(Main  ): Output, data= [ 0x02 ] 2
                            Data Variable Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Report Count, data= [ 0x01 ] 1
            Item(Global): Report Size, data= [ 0x03 ] 3
            Item(Main  ): Output, data= [ 0x01 ] 1
                            Constant Array Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Report Count, data= [ 0x06 ] 6
            Item(Global): Report Size, data= [ 0x08 ] 8
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0x65 ] 101
            Item(Global): Usage Page, data= [ 0x07 ] 7
                            Keyboard
            Item(Local ): Usage Minimum, data= [ 0x00 ] 0
                            No Event
            Item(Local ): Usage Maximum, data= [ 0x65 ] 101
                            Keyboard Application (Windows Key for Win95 or Compose)
            Item(Main  ): Input, data= [ 0x00 ] 0
                            Data Array Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Main  ): End Collection, data=none
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               none
        wMaxPacketSize          8
        bInterval              10
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Devices
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      2 Mouse
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.00
          bCountryCode            0
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      52
	  Report Descriptor: (length is 52)
            Item(Global): Usage Page, data= [ 0x01 ] 1
                            Generic Desktop Controls
            Item(Local ): Usage, data= [ 0x02 ] 2
                            Mouse
            Item(Main  ): Collection, data= [ 0x01 ] 1
                            Application
            Item(Local ): Usage, data= [ 0x01 ] 1
                            Pointer
            Item(Main  ): Collection, data= [ 0x00 ] 0
                            Physical
            Item(Global): Usage Page, data= [ 0x09 ] 9
                            Buttons
            Item(Local ): Usage Minimum, data= [ 0x01 ] 1
                            Button 1 (Primary)
            Item(Local ): Usage Maximum, data= [ 0x05 ] 5
                            (null)
            Item(Global): Logical Minimum, data= [ 0x00 ] 0
            Item(Global): Logical Maximum, data= [ 0x01 ] 1
            Item(Global): Report Count, data= [ 0x05 ] 5
            Item(Global): Report Size, data= [ 0x01 ] 1
            Item(Main  ): Input, data= [ 0x02 ] 2
                            Data Variable Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Report Count, data= [ 0x01 ] 1
            Item(Global): Report Size, data= [ 0x03 ] 3
            Item(Main  ): Input, data= [ 0x01 ] 1
                            Constant Array Absolute No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Global): Usage Page, data= [ 0x01 ] 1
                            Generic Desktop Controls
            Item(Local ): Usage, data= [ 0x30 ] 48
                            Direction-X
            Item(Local ): Usage, data= [ 0x31 ] 49
                            Direction-Y
            Item(Local ): Usage, data= [ 0x38 ] 56
                            Wheel
            Item(Global): Logical Minimum, data= [ 0x81 ] 129
            Item(Global): Logical Maximum, data= [ 0x7f ] 127
            Item(Global): Report Size, data= [ 0x08 ] 8
            Item(Global): Report Count, data= [ 0x03 ] 3
            Item(Main  ): Input, data= [ 0x06 ] 6
                            Data Variable Relative No_Wrap Linear
                            Preferred_State No_Null_Position Non_Volatile Bitfield
            Item(Main  ): End Collection, data=none
            Item(Main  ): End Collection, data=none
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               none
        wMaxPacketSize          4
        bInterval              10
  Language IDs: (length=4)
     0409 English(US)

Bus 002 Device 002: ID 046e:5403 Behavior Tech. Computer 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            9 Hub
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x046e Behavior Tech. Computer
  idProduct          0x5403 
  bcdDevice            0.01
  iManufacturer           1 BTC
  iProduct                2 USB Hub Keyboard   
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           25
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          2
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 
      iInterface              2 USB Hub Keyboard   
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               none
        wMaxPacketSize          1
        bInterval             255
  Language IDs: (length=4)
     0409 English(US)

Bus 002 Device 001: ID 0000:0000 Virtual Hub
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            9 Hub
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x0000 Virtual
  idProduct          0x0000 Hub
  bcdDevice            2.06
  iManufacturer           3 Linux 2.6.0-test9 ohci_hcd
  iProduct                2 OHCI Host Controller
  iSerial                 1 0000:a0:01.1
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           25
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0x40
      Self Powered
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               none
        wMaxPacketSize          2
        bInterval             255
  Language IDs: (length=4)
     0409 English(US)

Bus 001 Device 001: ID 0000:0000 Virtual Hub
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            9 Hub
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x0000 Virtual
  idProduct          0x0000 Hub
  bcdDevice            2.06
  iManufacturer           3 Linux 2.6.0-test9 ohci_hcd
  iProduct                2 OHCI Host Controller
  iSerial                 1 0000:a0:01.0
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           25
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0x40
      Self Powered
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               none
        wMaxPacketSize          2
        bInterval             255
  Language IDs: (length=4)
     0409 English(US)

<-- contents of /proc/bus/usb/devices -->

T:  Bus=02 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=12  MxCh= 2
B:  Alloc=  0/900 us ( 0%), #Int=  1, #Iso=  0
D:  Ver= 1.10 Cls=09(hub  ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=0000 ProdID=0000 Rev= 2.06
S:  Manufacturer=Linux 2.6.0-test9 ohci_hcd
S:  Product=OHCI Host Controller
S:  SerialNumber=0000:a0:01.1
C:* #Ifs= 1 Cfg#= 1 Atr=40 MxPwr=  0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub
E:  Ad=81(I) Atr=03(Int.) MxPS=   2 Ivl=255ms

T:  Bus=02 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  2 Spd=12  MxCh= 3
D:  Ver= 1.10 Cls=09(hub  ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=046e ProdID=5403 Rev= 0.01
S:  Manufacturer=BTC
S:  Product=USB Hub Keyboard   
C:* #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=100mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub
E:  Ad=81(I) Atr=03(Int.) MxPS=   1 Ivl=255ms

T:  Bus=02 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#=  4 Spd=12  MxCh= 0
D:  Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=046e ProdID=5303 Rev= 0.01
S:  Manufacturer=BTC
S:  Product=USB Hub Keyboard   
C:* #Ifs= 2 Cfg#= 1 Atr=e0 MxPwr=  0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=01 Prot=01 Driver=(none)
E:  Ad=81(I) Atr=03(Int.) MxPS=   8 Ivl=10ms
I:  If#= 1 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=00 Prot=00 Driver=(none)
E:  Ad=82(I) Atr=03(Int.) MxPS=   4 Ivl=255ms

T:  Bus=02 Lev=01 Prnt=01 Port=01 Cnt=02 Dev#=  3 Spd=1.5 MxCh= 0
D:  Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=050d ProdID=0119 Rev= 1.20
S:  Manufacturer=Belkin Components
S:  Product=USB-PS2 Adapter 
C:* #Ifs= 2 Cfg#= 1 Atr=a0 MxPwr=100mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=01 Prot=01 Driver=(none)
E:  Ad=81(I) Atr=03(Int.) MxPS=   8 Ivl=10ms
I:  If#= 1 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=01 Prot=02 Driver=(none)
E:  Ad=82(I) Atr=03(Int.) MxPS=   4 Ivl=10ms

T:  Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=12  MxCh= 3
B:  Alloc=  0/900 us ( 0%), #Int=  0, #Iso=  0
D:  Ver= 1.10 Cls=09(hub  ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=0000 ProdID=0000 Rev= 2.06
S:  Manufacturer=Linux 2.6.0-test9 ohci_hcd
S:  Product=OHCI Host Controller
S:  SerialNumber=0000:a0:01.0
C:* #Ifs= 1 Cfg#= 1 Atr=40 MxPwr=  0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub
E:  Ad=81(I) Atr=03(Int.) MxPS=   2 Ivl=255ms