If the backlight modulation frequency can't be extracted from the
registers or from VBT, use 200 Hz as the default. This may enable
backlight on some machines that previously failed.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Tested-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1448958232-26520-2-git-send-email-jani.nikula@intel.com