tree 725a104da46815cefdbb7c0099bba42cbcb46a6c
parent 4e8cb8acab1f6c72254eaf20e2bb69a980cb121b
author David Moore <david.moore@gmail.com> 1359008389 -0800
committer Matthias Kaehlcke <mka@google.com> 1433366102 -0700

usb: Prevent dead ports when xhci is not enabled

commit 58b2939b4d5a030eaec469d29812ab8477ee7e76 upstream.

When the xHCI driver is not available, actively switch the ports to EHCI
mode since some BIOSes leave them in xHCI mode where they would
otherwise appear dead.  This was discovered on a  Dell Optiplex 7010,
but it's possible other systems could be affected.

This should be backported to kernels as old as 3.0, that contain the
commit 69e848c2090aebba5698a1620604c7dccb448684 "Intel xhci: Support
EHCI/xHCI port switching."

Signed-off-by: David Moore <david.moore@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>