+procfs notes:
+
+The following commands can be written to the /proc/acpi/ibm/hotkey file:
+
+ echo enable > /proc/acpi/ibm/hotkey -- enable the hot keys feature
+ echo disable > /proc/acpi/ibm/hotkey -- disable the hot keys feature
+ echo 0xffff > /proc/acpi/ibm/hotkey -- enable all possible hot keys
+ echo 0x0000 > /proc/acpi/ibm/hotkey -- disable all possible hot keys
+ ... any other 4-hex-digit mask ...
+ echo reset > /proc/acpi/ibm/hotkey -- restore the original mask
+
+sysfs notes:
+
+ The hot keys attributes are in a hotkey/ subdirectory off the
+ thinkpad device.
+
+ bios_enabled:
+ Returns the status of the hot keys feature when
+ thinkpad-acpi was loaded. Upon module unload, the hot
+ key feature status will be restored to this value.
+
+ 0: hot keys were disabled
+ 1: hot keys were enabled
+
+ bios_mask:
+ Returns the hot keys mask when thinkpad-acpi was loaded.
+ Upon module unload, the hot keys mask will be restored
+ to this value.
+
+ enable:
+ Enables/disables the hot keys feature, and reports
+ current status of the hot keys feature.
+
+ 0: disables the hot keys feature / feature disabled
+ 1: enables the hot keys feature / feature enabled
+
+ mask:
+ bit mask to enable ACPI event generation for each hot
+ key (see above). Returns the current status of the hot
+ keys mask, and allows one to modify it.
+
+
+Bluetooth
+---------