Linux lsusb command explanation

[BlueAstra]

Some time ago someone on the forum suggested using the Linux lsusb command to find out if your usb hub has 32 bit buffers or not. It was felt that 32 bit buffers were more reliable. I've tried this, using lsusb -v, and get a huge list of data on the usb devices connected. I can identify the hub, but its not obvious which of the numbers that follow indicate the size of the buffer. I'm not a computer expert, so can anyone identify which part of the data after a lsusb -v command tells me the buffer size?

[michael.h.f.wilkinson]

Can you give a listing of the type of output you get (preferably just the relevant part)?

[NickK]

Also you will need to have administrator priviledges for some information (at least on ubuntu).

sudo lsusb -v

Then type in your root password.

You should note there's additional information.

[Shure]

I think it's the "bMaxPacketSize0" field but I am not 100%

[BlueAstra]

I don't have the ouput here. Will run it again this evening and attach the output.

This isn't the output, but its typical of the sort of output you get:

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Device Descriptor:

bLength 18

bDescriptorType 1

bcdUSB 2.00

bDeviceClass 9 Hub

bDeviceSubClass 0 Unused

bDeviceProtocol 1 Single TT

bMaxPacketSize0 64

idVendor 0x1d6b Linux Foundation

idProduct 0x0002 2.0 root hub

bcdDevice 2.06

iManufacturer 3 Linux 2.6.25-14.fc9.i686 ehci_hcd

iProduct 2 EHCI Host Controller

iSerial 1 0000:02:02.0

bNumConfigurations 1

Configuration Descriptor:

bLength 9

bDescriptorType 2

wTotalLength 25

bNumInterfaces 1

bConfigurationValue 1

iConfiguration 0

bmAttributes 0xe0

Self Powered

Remote Wakeup

MaxPower 0mA

Interface Descriptor:

bLength 9

bDescriptorType 4

bInterfaceNumber 0

bAlternateSetting 0

bNumEndpoints 1

bInterfaceClass 9 Hub

bInterfaceSubClass 0 Unused

bInterfaceProtocol 0 Full speed (or root) hub

iInterface 0

Endpoint Descriptor:

bLength 7

bDescriptorType 5

bEndpointAddress 0x81 EP 1 IN

bmAttributes 3

Transfer Type Interrupt

Synch Type None

Usage Type Data

wMaxPacketSize 0x0004 1x 4 bytes

bInterval 12

Hub Descriptor:

bLength 9

bDescriptorType 41

nNbrPorts 6

wHubCharacteristic 0x000a

No power switching (usb 1.0)

Per-port overcurrent protection

TT think time 8 FS bits

bPwrOn2PwrGood 10 * 2 milli seconds

bHubContrCurrent 0 milli Ampere

DeviceRemovable 0x00

PortPwrCtrlMask 0xff

Hub Port Status:

Port 1: 0002.0503 C_ENABLE highspeed power enable connect

Port 2: 0000.0100 power

Port 3: 0000.0100 power

Port 4: 0000.0100 power

Port 5: 0000.0100 power

Port 6: 0000.0100 power

Device Status: 0x0003

Self Powered

Remote Wakeup Enabled

[michael.h.f.wilkinson]

I think it is the field wMaxPacketSize 0x0004 1x 4 bytes (=32 bits)