Commit 0de7fb7c authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI: scan: Avoid unnecessary second pass in acpi_bus_scan() 



If there are no devices whose enumeration has been deferred after
the first pass in acpi_bus_scan(), the second pass is not necssary,
so avoid it with the help of a new static variable.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
Tested-by: default avatarHans de Goede <hdegoede@redhat.com>
Reviewed-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
parent 71da201f

drivers/acpi/scan.c

+10 −1
Original line number Diff line number Diff line
@@ -1910,6 +1910,8 @@ static void acpi_scan_dep_init(struct acpi_device *adev) 
	mutex_unlock(&acpi_dep_list_lock);

}



static bool acpi_bus_scan_second_pass;



static acpi_status acpi_bus_check_add(acpi_handle handle, bool check_dep,

				      struct acpi_device **adev_p)

{
@@ -1934,9 +1936,11 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, bool check_dep, 
	if (type == ACPI_BUS_TYPE_DEVICE && check_dep) {

		u32 count = acpi_scan_check_dep(handle);

		/* Bail out if the number of recorded dependencies is not 0. */

		if (count > 0)

		if (count > 0) {

			acpi_bus_scan_second_pass = true;

			return AE_CTRL_DEPTH;

		}

	}



	acpi_add_single_object(&device, handle, type, sta);

	if (!device)
@@ -2136,6 +2140,8 @@ int acpi_bus_scan(acpi_handle handle) 
{

	struct acpi_device *device = NULL;



	acpi_bus_scan_second_pass = false;



	/* Pass 1: Avoid enumerating devices with missing dependencies. */



	if (ACPI_SUCCESS(acpi_bus_check_add(handle, true, &device)))
@@ -2148,6 +2154,9 @@ int acpi_bus_scan(acpi_handle handle) 


	acpi_bus_attach(device, true);



	if (!acpi_bus_scan_second_pass)

		return 0;



	/* Pass 2: Enumerate all of the remaining devices. */



	device = NULL;

CRA Git | Maintained and supported by SUSTech CRA and CCSE