I installed ubuntu server 14.04 on a new server machine. I was planning to get an external usb hard disk for data backup purposes. My motherboard is intel s1200V3RPS which shows on intel page usb 3.0 with 4 ports. However, I have 6 ports on my machine and when i do lsusb on it I get the following output

naveen@ubserver:~/ordcode$ lsusb
Bus 002 Device 002: ID 8087:8000 Intel Corp. 
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8008 Intel Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 058: ID 413c:9013 Dell Computer Corp. 
Bus 003 Device 004: ID 046b:ff10 American Megatrends, Inc. Virtual Keyboard and Mouse
Bus 003 Device 031: ID 046d:c05a Logitech, Inc. M90/M100 Optical Mouse
Bus 003 Device 002: ID 046d:c31c Logitech, Inc. Keyboard K120 for Business
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

This shows 4 buses with 8 devices and most have 2.0 root hub and only one is 3.0 root hub? Does this mean that only one port of mine supports usb 3.0?

  • This question might be off-topic as it's not specific to Ubuntu. I think it belongs to unix.se. – kraxor Jun 20 '14 at 13:00

lsusb only print the USB root hubs and devices that are connected to them. For instance your keyboard and mouse are both on bus 003, that is a root hub 2.0.

A root hub is a USB-device, that distributes the USB-signal over multiple ports. So your ouput only means, that there is just one USB 3.0 hub. But you can connect multiple devices on it.

The USB subsystem has the form of a tiered star:

tiered star

Additional USB hubs may be included in the tiers, allowing branching into a tree structure with up to five tier levels.

  • Thanks! Pardon my naivety but on some research I found out that usb 3.0 ports are blue. On my server, I can see at least 3 such ports. Does that mean I have 3 usb 3.0 ports? Any way to verify this? – Naveen Sharma Jun 20 '14 at 13:27
  • Ur welcome. Yes, that means you have 3 3.0 ports. But you can add an USB hub there and have more than 3 ports, but altogether they cannot go over 5Gbps. Via software you cannot list the effectve number of hardware usb ports your machine has. – chaos Jun 20 '14 at 13:54

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