Two USB ports stopped working

Here I got my USB3 ports not working after a while: only a restart fixes the problem.

After some research, I've found that a lot of USB3 ports presents a power management problem In a lot of different hardwares and OSs. You can find people reporting this kind of problem on Windows, Linux, etc.

So, I've disabled USB power management, and now everything is fine.

1. Disabling USB Power Management

For Ubuntu, usbcore module is compiled in the kernel, so we need to change the kernel boot parameters.

Edit the /etc/default/grub file and change the GRUB_CMDLINE_LINUX_DEFAULT line to add the usbcore.autosuspend=-1 option:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash usbcore.autosuspend=-1"

Note that quit splash were options already present. So keep other options you have too.

Save file and close.

2. Update grub

After save the file, update grub:

sudo update-grub

And reboot.

3. Check autosuspend after reboot

After reboot, check autosuspend value:

cat /sys/module/usbcore/parameters/autosuspend

And it should display -1.

I had a similar problem and http://www.ubuntugeek.com/how-to-fix-usb-stops-working-problem-in-ubuntu.html lists another way to fix this

This method also edits the grub but instead of modifying GRUB_CMDLINE_LINUX_DEFAULT it modifies GRUB_CMDLINE_LINUX="".

Steps:

1. Open terminal
2. Type gksudo gedit /etc/default/grub in terminal and press enter
3. Find the line GRUB_CMDLINE_LINUX=""
4. Modify the line to read GRUB_CMDLINE_LINUX="acpi=force irqpoll"
5. After that, update the bootloader via terminal by typing sudo update-grub and pressing enter
6. Restart your system

This method is the same as given in the link above and it worked for me.

I use Ubuntu Desktop 14.04 64 bit.