USB 3.0 port being seen as a USB 2.0 port

Question

As the title says, my system doesn't seem to recognize my USB 3.0. It instead claims to be a 2.0. Any help would be appreciated!

My computer is the Asus Q200E. It's pretty bad, but it works for school. Except for this damn usb 3.0 port

    lsusb -t
/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M
    |__ Port 2: Dev 25, If 0, Class=Human Interface Device, Driver=usbhid, 480M
    |__ Port 3: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 12M
    |__ Port 3: Dev 2, If 1, Class=Human Interface Device, Driver=usbhid, 12M
    |__ Port 3: Dev 2, If 2, Class=Human Interface Device, Driver=usbhid, 12M
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
        |__ Port 2: Dev 14, If 0, Class=Video, Driver=uvcvideo, 480M
        |__ Port 2: Dev 14, If 1, Class=Video, Driver=uvcvideo, 480M
        |__ Port 3: Dev 4, If 0, Class=Human Interface Device, Driver=usbhid, 12M
        |__ Port 3: Dev 4, If 1, Class=Human Interface Device, Driver=usbhid, 12M

pic from hardinfo (highlighted part is what's connected to the supposed 3.0 port)

proof port and usb a are both 3.0 compatible

Solution

Hi the following procedures will fix your problem right away.

1. Open terminal
2. Backup your grub config by entering sudo cp /etc/default/grub /etc/default/grub.backup (note: this is the location of the grub config in recent Ubuntu versions, the location of your file may differ based on distro and version)
3. Open your grub file: sudo nano /etc/default/grub
4. Find the line that begins with GRUB_CMDLINE_LINUX_DEFAULT and add iommu=soft after "quiet splash" and before the quotation mark "quiet splash iommu=soft".
5. Save the file by hitting Ctrl-O and then exit with Ctrl-X
6. Enter update-grub in terminal and hit enter to update your grub.cfg
7. Restart your machine to let the changes take place.

Comments

[Terrance]

Can you edit your question and copy and paste the output of sudo lsusb -t from a terminal window?

[Terrance]

Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M is USB 3.0. The 5000M means 5GHz for the speed. To obtain those speeds you need to plug in an actual device that is USB 3.0. Plugging in a USB 2.0 device into a 3.0 port will slow down to the 480Mb of USB 2.0.

[J-Lit]

Hmm weird, I geuss I thought my device was USB 3.0 compatible, but I can't find anywhere that says it is. My mistake, thanks for the info!

[Terrance]

My bad, that's supposed to be 5Gb not 5GHz. Anyway, you can run that lsusb command again with your device plugged in and see.

[Meki]

Would you go into a bit more detailed explanation on how adding iommu=soft would solve the problem?