ACPI: scan: Reduce overhead related to devices with dependencies

Notice that all of the objects for which the acpi_scan_check_dep()
return value is greater than 0 are present in acpi_dep_list as consumers
(there may be multiple entries for one object, but that is not a
problem), so after carrying out the initial ACPI namespace walk in which
devices with dependencies are skipped, acpi_bus_scan() can simply walk
acpi_dep_list and enumerate all of the unique consumer objects from
there and their descendants instead of walking the entire target branch
of the ACPI namespace and looking for device objects that have not been
enumerated yet in it.

Because walking acpi_dep_list is generally less overhead than walking
the entire ACPI namespace, use the observation above to reduce the
system initialization overhead related to ACPI, which is particularly
important on large systems.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index a6affc0550b0..c941d99162c0 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -289,6 +289,8 @@ struct acpi_dep_data {
 	acpi_handle supplier;
 	acpi_handle consumer;
 	bool honor_dep;
+	bool met;
+	bool free_when_met;
 };
 
 /* Performance Management */