• Ravi Chandra Sadineni's avatar
    USB: Increment wakeup count on remote wakeup. · 83a62c51
    Ravi Chandra Sadineni authored
    On chromebooks we depend on wakeup count to identify the wakeup source.
    But currently USB devices do not increment the wakeup count when they
    trigger the remote wake. This patch addresses the same.
    
    Resume condition is reported differently on USB 2.0 and USB 3.0 devices.
    
    On USB 2.0 devices, a wake capable device, if wake enabled, drives
    resume signal to indicate a remote wake (USB 2.0 spec section 7.1.7.7).
    The upstream facing port then sets C_PORT_SUSPEND bit and reports a
    port change event (USB 2.0 spec section 11.24.2.7.2.3). Thus if a port
    has resumed before driving the resume signal from the host and
    C_PORT_SUSPEND is set, then the device attached to the given port might
    be the reason for the last system wakeup. Increment the wakeup count for
    the same.
    
    On USB 3.0 devices, a function may signal that it wants to exit from device
    suspend by sending a Function Wake Device Notification to the host (USB3.0
    spec section 8.5.6.4) Thus on receiving the Function Wake, increment the
    wakeup count.
    Signed-off-by: default avatarRavi Chandra Sadineni <ravisadineni@chromium.org>
    Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    83a62c51
hub.c 167 KB