Plumb link status BAD to OnHotplugEvent composer callback
This updates the Uevent handler to handle the hotplug events sent by the kernel for link training failure. Adds support in hotplug handler in resourcemanager to read connector properties and read the value of link-status property. If this is set to DRM_MODE_LINK_STATUS_BAD, then invoke the OnHotplugEvent() composer callback with the BAD CABLE DisplayHotplugEvent to notify the Surfaceflinger about link training failure.
Currently this uses the ERROR_INCOMPATIBLE_CABLE field of the DisplayHotplugEvent callback. The longer term would be to define a new field in this enum to indicate MODESET_RETRY and use this INCOMPATIBLE_CABLE for the terminal link train failure state.
Change-Id: I823d7570dd08e476d0c887e350bce3f8f0069afb Signed-off-by: Manasi Navare navaremanasi@chromium.org