From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
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: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/acpi/scan.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -1910,6 +1910,8 @@ static void acpi_scan_dep_init(struct ac
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)
{
@@ -1934,8 +1936,10 @@ static acpi_status acpi_bus_check_add(ac
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);
@@ -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;
