Comment 92 for bug 1419355

(In reply to gdl from comment #85)
> Arch Linux 3.15.7-1

gdl, as your kernel is newer than 3.14, you should be able to apply an easy workaround with module options.

Try these lines in /etc/modprobe.d/xhci.conf (create the file if it does not exist), one at a time:

options xhci-hcd quirks=270336

options xhci-hcd quirks=8192

options xhci-hcd quirks=262144

The first setting enables both XHCI_SPURIOUS_WAKEUP and XHCI_SPURIOUS_REBOOT quirks, the second only XHCI_SPURIOUS_REBOOT and the third only XHCI_SPURIOUS_WAKEUP.

After editing /etc/modprobe.d/xhci.conf, you'll need to run "depmod" and/or recreate your initrd/initramfs, reboot, then see if power-off works.

If your kernel configuration includes the xhci-hcd as built-in instead of as a module, these boot options should be equivalent (again, try just one at a time):

xhci_hcd.quirks=270336

xhci_hcd.quirks=8192

xhci_hcd.quirks=262144

If one or more of these works, please report which quirks setting(s) worked and which did not.