Ubuntu 20.04.1 usb no longer functioning

Ubuntu 20.04.1 abruptly stopped recognizing USB devices on the machine my kids use. Have tried with a mouse, a game controller, and a USB stick on different ports without success, all work when plugged into a different machine.

The computer is a Lenovo Yoga 900-131SK.

I have tried making each of the following changes to /etc/default/grub, updating grub, and then rebooting, without success:

GRUB_CMDLINE_LINUX=""to GRUB_CMDLINE_LINUX="acpi=force irqpoll"
GRUB_CMDLINE_LINUX=""to GRUB_CMDLINE_LINUX="iommu=soft"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" to GRUB_CMDLINE_LINUX_DEFAULT="quiet splash usbcore.autosuspend=-1"

I also tried chmod 777 /media/ without succcess.

I've seen a number of suggestions to check the BIOS to see whether USB is disabled there, but BIOS has been inaccessible (nonexistent?) on this machine since well before the problem emerged. (That's a Windows issue, apparently -- I was trying to set this up to dual-boot.)

Several programs were installed prior to the problem appearing: ri-li, kgeography, and childsplay. I've uninstalled all of them and rebooted with no change in behavior.

Output of lsusb with USB mouse plugged in is:
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 8087:0a2b Intel Corp.
Bus 001 Device 002: ID 0bda:57e1 Realtek Semiconductor Corp. Lenovo EasyCamera
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

That covers every suggestion I've been able to find. Any other ideas would be welcome.

1 Answer

Solved (at least enough). I edited /etc/default/grub to change the line GRUB_CMDLINE_LINUX="acpi=force irqpoll' (as I had previously attempted) and swapped the USB port for the mouse. One of the ports now functions, but not the other, so presumably I was testing the mouse in the still non-functioning port. I'm not sure why that wasn't functioning, but it's not mission-critical, so I'm closing this.