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  • Lee, Chiasheng's avatar
    usb: Handle USB3 remote wakeup for LPM enabled devices correctly · e244c469
    Lee, Chiasheng authored
    
    
    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: default avatarLee, Chiasheng <chiasheng.lee@intel.com>
    Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    e244c469