dell-wmi: mask off upper bytes of event response

In debugging with some future machines that actually contain BIOS level
support for dell-wmi, I've determined that the upper half of the data that
comes back from wmi_get_event_data may sometimes contain extra information
that isn't currently relevant when pulling scan codes out of the data.
This causes dell-wmi to improperly respond to these events.

Signed-off-by: Mario Limonciello <mario_limonciello@dell.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
index 2fab94162147..8a0d39ee9217 100644
--- a/drivers/platform/x86/dell-wmi.c
+++ b/drivers/platform/x86/dell-wmi.c
@@ -122,7 +122,12 @@ static void dell_wmi_notify(u32 value, void *context)
 
         if (obj && obj->type == ACPI_TYPE_BUFFER) {
                 int *buffer = (int *)obj->buffer.pointer;
-                key = dell_wmi_get_entry_by_scancode(buffer[1]);
+                /*
+                 *  The upper bytes of the event may contain
+                 *  additional information, so mask them off for the
+                 *  scancode lookup
+                 */
+                key = dell_wmi_get_entry_by_scancode(buffer[1] & 0xFFFF);
                 if (key) {
                         input_report_key(dell_wmi_input_dev, key->keycode, 1);
                         input_sync(dell_wmi_input_dev);