USB 3.0 device only works in 3.1 Gen 2 port?

[1fallen]

hey h2, I've found on most of my Devices/Computers:
*** My theory is that usb "legacy" conflicts with the os's understanding of 3.0,

You can check your USB devices with:

lsusb -t

There should also be listed which driver is in use and at which speed the devices are connected.
EX:

/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 10000M
/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 480M
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 10000M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/12p, 480M
    |__ Port 3: Dev 2, If 0, Class=Mass Storage, Driver=uas, 480M
    |__ Port 8: Dev 3, If 1, Class=Video, Driver=uvcvideo, 480M
    |__ Port 8: Dev 3, If 0, Class=Video, Driver=uvcvideo, 480M
    |__ Port 9: Dev 4, If 0, Class=Vendor Specific Class, Driver=, 12M
    |__ Port 10: Dev 5, If 0, Class=Wireless, Driver=btusb, 12M
    |__ Port 10: Dev 5, If 1, Class=Wireless, Driver=btusb, 12M

>>> back into bios, have usb 3.0 turned on, and any other options turned on, but turn off legacy usb option. (If available)

Also you could also try adding, "iommu=soft" to the boot parameters.

My understanding, "iommu=soft" means use some "software" version of iommu instead of "hardware" support from the motherboard. Also, the iommu=pt parameter should prevent Linux from touching devices which cannot be passed through.

What I have noticed though throughout the years transfer speeds vary from 120mb's to 50-60mb's

[halogen2]

>>> back into bios, have usb 3.0 turned on, and any other options turned on, but turn off legacy usb option. (If available)

Tried Legacy USB mode set to Auto and Disabled, both with xHCI Hand-off Enabled. Unfortunately it didn't make any difference

Also you could also try adding, "iommu=soft" to the boot parameters.

This did not make any difference either, nor did iommu=pt. But I didn't leave the EFI settings changes in place while trying this, I had reset the EFI settings after seeing those changes not help. To be clear, should I have done all this at once?

[1fallen]

To be clear, should I have done all this at once?

As of this point now, when booting...select kernel...press "e" then add <iommu=soft> to the kernel line:

GRUB_CMDLINE_LINUX_DEFAULT=

I'm not sure how you added it, but if you edited "/etc/default/grub" and then updated-grub for the system to use that new parameter. Without messing in UEFI or Bios this run.

[halogen2]

you edited "/etc/default/grub" and then updated-grub for the system to use that new parameter.

Yes, that's how I added the boot parameter.

To be clear, should I have done all this at once?

I went ahead and tested anyway doing all the combinations of both the EFI changes and iommu= boot parameter changes 1fallen mentioned. Sadly, none of it helped

I'm thinking maybe at this point I would best shelve this until I can update the kernel or entire OS to a more recent version (or if I receive a EFI update?). But I'd appreciate any other suggestions

[1fallen]

Well at least we figured out a couple more ways that don't work.

[halogen2]

For unrelated reasons, I now have also a laptop, also System76 brand. There this issue only occurs in one USB 3 port, while a second USB 3 port and the USB 2.0 port have no problem handling this device. That's good enough for me that I didn't bother testing the USB-C port.

Since I have now at least three USB ports that work with the device, I no longer feel uncomfortable just living with this. Still, I'd rather have this working if possible.

* I have now tested this in Pop!_OS 21.04 on the Thelio Major. No difference to this issue.

[halogen2]

Found a workaround. I plugged in a USB 2.0 hub into one of the problematic USB 3.0 ports, and then plugged in my adapter into that USB 2.0 hub. And it works!

So, solved for purpose of this forum thread. But I probably should try to reach out to System76 about this, I would think something is wrong if I have to hardware-force USB 2.0 on a USB 3.0 device.