I want to buy an external USB 3.0 drive and I wonder how to figure out whether my laptop has such a port (or only 2.0).
Neither lsusb -v, nor /proc/bus/input/devices offers any obvious hints, although the former says a lot of 2.0 root hub which might imply v2 and not v3. Right?
lsusb does show you whether the kernel sees usb 3.0 support.
Contrast this non-USB3 system:
$ lsusb
Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 1210:2604 DigiTech
Bus 002 Device 003: ID 0a5c:219c Broadcom Corp.
with this one, which does support USB3:
$ lsusb
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 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 001 Device 003: ID 08ff:168b AuthenTec, Inc.
Bus 001 Device 004: ID 04f2:b1d6 Chicony Electronics Co., Ltd
Bus 002 Device 015: ID 0cf3:3005 Atheros Communications, Inc. AR3011 Bluetooth
a "3.0 root hub" is present for USB3.
That said, I concur that the best way to determine if your hardware is USB3 is by looking at the ports themselves; USB3 is usually color-coded and is blue, and has some extra conductors (which are however a bit difficult to see). If a USB 3.0 port is not blue, you will most likely see the phrase "SS" for super speed next to it, like this:
