ACPI: WMI: Enable event methods when registering notifiers

According to the ACPI-WMI spec, event blocks may provide a function call
for enabling/disabling them. This patch adds support for making these
calls when registering or removing notifications. Without this, my Dell
firmware provides no data in the event notification.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 37 insertions, 2 deletions

diff --git a/drivers/acpi/wmi.c b/drivers/acpi/wmi.c
index cfe2c833474d..5464cfcf8297 100644
--- a/drivers/acpi/wmi.c
+++ b/drivers/acpi/wmi.c
@@ -217,6 +217,35 @@ static bool find_guid(const char *guid_string, struct wmi_block **out)
         return 0;
 }
 
+static acpi_status wmi_method_enable(struct wmi_block *wblock, int enable)
+{
+        struct guid_block *block = NULL;
+        char method[5];
+        struct acpi_object_list input;
+        union acpi_object params[1];
+        acpi_status status;
+        acpi_handle handle;
+
+        block = &wblock->gblock;
+        handle = wblock->handle;
+
+        if (!block)
+                return AE_NOT_EXIST;
+
+        input.count = 1;
+        input.pointer = params;
+        params[0].type = ACPI_TYPE_INTEGER;
+        params[0].integer.value = enable;
+
+        snprintf(method, 5, "WE%02X", block->notify_id);
+        status = acpi_evaluate_object(handle, method, &input, NULL);
+
+        if (status != AE_OK && status != AE_NOT_FOUND)
+                return status;
+        else
+                return AE_OK;
+}
+
 /*
  * Exported WMI functions
  */
@@ -427,6 +456,7 @@ acpi_status wmi_install_notify_handler(const char *guid,
 wmi_notify_handler handler, void *data)
 {
         struct wmi_block *block;
+        acpi_status status;
 
         if (!guid || !handler)
                 return AE_BAD_PARAMETER;
@@ -441,7 +471,9 @@ wmi_notify_handler handler, void *data)
         block->handler = handler;
         block->handler_data = data;
 
-        return AE_OK;
+        status = wmi_method_enable(block, 1);
+
+        return status;
 }
 EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
 
@@ -453,6 +485,7 @@ EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
 acpi_status wmi_remove_notify_handler(const char *guid)
 {
         struct wmi_block *block;
+        acpi_status status;
 
         if (!guid)
                 return AE_BAD_PARAMETER;
@@ -464,10 +497,12 @@ acpi_status wmi_remove_notify_handler(const char *guid)
         if (!block->handler)
                 return AE_NULL_ENTRY;
 
+        status = wmi_method_enable(block, 0);
+
         block->handler = NULL;
         block->handler_data = NULL;
 
-        return AE_OK;
+        return status;
 }
 EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);