usb: Handle USB3 remote wakeup for LPM enabled devices correctly
authorLee, Chiasheng <chiasheng.lee@intel.com>
Thu, 20 Jun 2019 07:56:04 +0000 (10:56 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 26 Jul 2019 07:14:30 +0000 (09:14 +0200)
commit91da712ff592ef3bb1f09060eae0fa391769fbdf
tree077c5b0f318a3b0bb231c5c9a2702b1535f63844
parent152ddf9f0458331912657c381276fc0677e8fc13
usb: Handle USB3 remote wakeup for LPM enabled devices correctly

commit e244c4699f859cf7149b0781b1894c7996a8a1df upstream.

With Link Power Management (LPM) enabled USB3 links transition to low
power U1/U2 link states from U0 state automatically.

Current hub code detects USB3 remote wakeups by checking if the software
state still shows suspended, but the link has transitioned from suspended
U3 to enabled U0 state.

As it takes some time before the hub thread reads the port link state
after a USB3 wake notification, the link may have transitioned from U0
to U1/U2, and wake is not detected by hub code.

Fix this by handling U1/U2 states in the same way as U0 in USB3 wakeup
handling

This patch should be added to stable kernels since 4.13 where LPM was
kept enabled during suspend/resume

Cc: <stable@vger.kernel.org> # v4.13+
Signed-off-by: Lee, Chiasheng <chiasheng.lee@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/core/hub.c