[BUGFIX v2 1/4] ACPI, DOCK: initialize dock subsystem before scanning PCI root buses

[Jiang Liu]

Changeset "3b63aaa70e1 PCI: acpiphp: Do not use ACPI PCI subdriver
mechanism" causes a regression which breaks ACPI dock support,
please refer to https://bugzilla.kernel.org/show_bug.cgi?id=59501

The root cause is that changeset 3b63aaa70e1 changed the relative
initialization order of ACPI dock subsystem and acpiphp driver,
and acpiphp driver has dependency on ACPI dock subsystem's
initialization result, so that acpiphp can't correctly detect ACPI
dock stations now.

On the other hand, ACPI dock is a built-in driver, so we could
explicitly initialize it before the acpiphp driver is used.

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
Reported-by: Alexander E. Patrakov <patrakov@xxxxxxxxx>
Tested-by: Alexander E. Patrakov <patrakov@xxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>
Cc: linux-acpi@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # 3.9+
---
 drivers/acpi/dock.c     | 7 +------
 drivers/acpi/internal.h | 5 +++++
 drivers/acpi/scan.c     | 1 +
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
index 4fdea38..02b0563 100644
--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -1033,7 +1033,7 @@ 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;
@@ -1062,9 +1062,4 @@ static void __exit dock_exit(void)
 		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);
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 297cbf4..c610a76 100644
--- a/drivers/acpi/internal.h
+++ b/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
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 44225cb..4148163 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2045,6 +2045,7 @@ int __init acpi_scan_init(void)
 	acpi_lpss_init();
 	acpi_container_init();
 	acpi_memory_hotplug_init();
+	acpi_dock_init();
 
 	mutex_lock(&acpi_scan_lock);
 	/*
-- 
1.8.1.2

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