This patch takes care of the race condition between the Function Wake
Device Notification and the auto-suspend timeout for this situation:
Roothub
| (U3)
hub A
| (U3)
hub B
| (U3)
device C
When device C signals a resume, the xHCI driver will set the wakeup_bits
for the roothub port that hub A is attached to. However, since USB 3.0
hubs do not set a link state change bit on device-initiated resume, hub
A will not indicate a port event when polled. Without this patch, khubd
will notice the wakeup-bits are set for the roothub port, it will resume
hub A, and then it will poll the events bits for hub A and notice that
nothing has changed. Then it will be suspended after 2 seconds.
Change hub_activate() to look at the port link state for each USB 3.0
hub port, and set hub->change_bits if the link state is U0, indicating
the device has finished resume. Change the resume function called by
hub_events(), hub_handle_remote_wakeup(), to check the link status
for resume instead of just the port's wakeup_bits.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
72937e1e34