tree 6c12ba489987e9a92e37d6f70293afb5e92c3fd2
parent 3e62fcdb1ef54256b9ad29870a510cab39cd80e7
author Duncan Laurie <dlaurie@chromium.org> 1380143312 -0700
committer chrome-internal-fetch <chrome-internal-fetch@google.com> 1380229483 +0000

lynxpoint: work around XHCI resume issues

When USB3 devices are attached while in suspend, or two USB3 devices
that are both plugged in are switched to the other port while in
suspend the kernel does not seem to notice this -- despite the cold
attach status bit.  This results in the devices showing up in the USB
list at the old enumerated device numbers and higher layers continuing
to think they are present but not reseponding.

With the kernel workaround to deal with devices that are logically
disconnected it is possible for firmware to send a warm port reset to
devices that are in this state and then the kernel will see them disappear
and handle it properly.

This same issue exists in the EFI firmware on the Whitetip Mountain 2
reference board so it is not specifically a coreboot bug.  If this
behavior is fixed in the kernel then this workaround could be removed
since it is in RW firmware.

BUG=chrome-os-partner:22818
BRANCH=falco,peppy,wolf,leon
TEST=manual:

1) attach two USB3 devices
2) suspend system
3) switch the ports that the USB3 devices are attatched to
4) resume system
5) confirm that the devices are re-enumerated and come up properly

Original-Change-Id: Ifba3ffc94a06dc0b2436d7d7d464d824657362af
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/170335
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
(cherry picked from commit 203d200268f4af6445224962190cbc66ad2a83e4)

Change-Id: I54fd2847ee25a60f25c2cefebdc1a3c18455464a
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/170579