ACPI / dock: Initialize ACPI dock subsystem upfront

Commit 3b63aaa70e (PCI: acpiphp: Do not use ACPI PCI subdriver
mechanism) introduced an ACPI dock support regression, because it
changed the relative initialization order of the ACPI dock subsystem
and the ACPI-based PCI hotplug (acpiphp).

Namely, the ACPI dock subsystem has to be initialized before
acpiphp_enumerate_slots() is first run, which after commit
3b63aaa70e happens during the initial enumeration of the PCI
hierarchy triggered by the initial ACPI namespace scan in
acpi_scan_init().  For this reason, the dock subsystem has to be
initialized before the initial ACPI namespace scan in
acpi_scan_init().

To make that happen, modify the ACPI dock subsystem to be
non-modular and add the invocation of its initialization routine,
acpi_dock_init(), to acpi_scan_init() directly before the initial
namespace scan.

[rjw: Changelog, removal of dock_exit().]
References: https://bugzilla.kernel.org/show_bug.cgi?id=59501
Reported-and-tested-by: Alexander E. Patrakov <patrakov@gmail.com>
Tested-by: Illya Klymov <xanf@xanf.me>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: 3.9+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/dock.c

@@ -993,30 +993,6 @@ err_unregister:
 	return ret;
 }
 
-/**
- * dock_remove - free up resources related to the dock station
- */
-static int dock_remove(struct dock_station *ds)
-{
-	struct dock_dependent_device *dd, *tmp;
-	struct platform_device *dock_device = ds->dock_device;
-
-	if (!dock_station_count)
-		return 0;
-
-	/* remove dependent devices */
-	list_for_each_entry_safe(dd, tmp, &ds->dependent_devices, list)
-		kfree(dd);
-
-	list_del(&ds->sibling);
-
-	/* cleanup sysfs */
-	sysfs_remove_group(&dock_device->dev.kobj, &dock_attribute_group);
-	platform_device_unregister(dock_device);
-
-	return 0;
-}
-
 /**
  * find_dock_and_bay - look for dock stations and bays
  * @handle: acpi handle of a device
@@ -1035,7 +1011,7 @@ find_dock_and_bay(acpi_handle handle, u32 lvl, void *context, void **rv)
 	return AE_OK;
 }
 
-static int __init dock_init(void)
+int __init acpi_dock_init(void)
 {
 	if (acpi_disabled)
 		return 0;
@@ -1054,19 +1030,3 @@ static int __init dock_init(void)
 		ACPI_DOCK_DRIVER_DESCRIPTION, dock_station_count);
 	return 0;
 }
-
-static void __exit dock_exit(void)
-{
-	struct dock_station *tmp, *dock_station;
-
-	unregister_acpi_bus_notifier(&dock_acpi_notifier);
-	list_for_each_entry_safe(dock_station, tmp, &dock_stations, sibling)
-		dock_remove(dock_station);
-}
-
-/*
- * Must be called before drivers of devices in dock, otherwise we can't know
- * which devices are in a dock
- */
-subsys_initcall(dock_init);
-module_exit(dock_exit);

drivers/acpi/internal.h

@@ -40,6 +40,11 @@ void acpi_container_init(void);
 #else
 static inline void acpi_container_init(void) {}
 #endif
+#ifdef CONFIG_ACPI_DOCK
+void acpi_dock_init(void);
+#else
+static inline void acpi_dock_init(void) {}
+#endif
 #ifdef CONFIG_ACPI_HOTPLUG_MEMORY
 void acpi_memory_hotplug_init(void);
 #else

drivers/acpi/scan.c

@@ -2042,6 +2042,7 @@ int __init acpi_scan_init(void)
 	acpi_lpss_init();
 	acpi_container_init();
 	acpi_memory_hotplug_init();
+	acpi_dock_init();
 
 	mutex_lock(&acpi_scan_lock);
 	/*