ACPI / EC: Use busy polling mode when GPE is not enabled

ACPI / EC: Use busy polling mode when GPE is not enabled

BugLink: http://bugs.launchpad.net/bugs/1687045
commit c3a696b6e8f8f75f9f75e556a9f9f6472eae2655 upstream.

When GPE is not enabled, it is not efficient to use the wait polling mode
as it introduces an unexpected scheduler delay.
So before the GPE handler is installed, this patch uses busy polling mode
for all EC(s) and the logic can be applied to non boot EC(s) during the
suspend/resume process.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=191561
Tested-by: Jakobus Schurz <jakobus.schurz@gmail.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>