1 files changed, 5 insertions, 1 deletions

diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index e2ddcdeb61b6..ab4b58eaa7f4 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -240,9 +240,13 @@ sysfs notes:
                 Returns 0.
 
         hotkey_bios_mask:
+                DEPRECATED, DON'T USE, WILL BE REMOVED IN THE FUTURE.
+
                 Returns the hot keys mask when thinkpad-acpi was loaded.
                 Upon module unload, the hot keys mask will be restored
-                to this value.
+                to this value.   This is always 0x80c, because those are
+                the hotkeys that were supported by ancient firmware
+                without mask support.
 
         hotkey_enable:
                 DEPRECATED, WILL BE REMOVED SOON.