+ hotkey_mask:
+ bit mask to enable driver-handling and ACPI event
+ generation for each hot key (see above). Returns the
+ current status of the hot keys mask, and allows one to
+ modify it.
+
+ hotkey_all_mask:
+ bit mask that should enable event reporting for all
+ supported hot keys, when echoed to hotkey_mask above.
+ Unless you know which events need to be handled
+ passively (because the firmware *will* handle them
+ anyway), do *not* use hotkey_all_mask. Use
+ hotkey_recommended_mask, instead. You have been warned.
+
+ hotkey_recommended_mask:
+ bit mask that should enable event reporting for all
+ supported hot keys, except those which are always
+ handled by the firmware anyway. Echo it to
+ hotkey_mask above, to use.
+
+ hotkey_radio_sw:
+ if the ThinkPad has a hardware radio switch, this
+ attribute will read 0 if the switch is in the "radios
+ disabled" postition, and 1 if the switch is in the
+ "radios enabled" position.
+
+ hotkey_report_mode:
+ Returns the state of the procfs ACPI event report mode
+ filter for hot keys. If it is set to 1 (the default),
+ all hot key presses are reported both through the input
+ layer and also as ACPI events through procfs (but not
+ through netlink). If it is set to 2, hot key presses
+ are reported only through the input layer.
+
+ This attribute is read-only in kernels 2.6.23 or later,
+ and read-write on earlier kernels.
+
+ May return -EPERM (write access locked out by module
+ parameter) or -EACCES (read-only).
+
+input layer notes:
+
+A Hot key is mapped to a single input layer EV_KEY event, possibly
+followed by an EV_MSC MSC_SCAN event that shall contain that key's scan
+code. An EV_SYN event will always be generated to mark the end of the
+event block.
+
+Do not use the EV_MSC MSC_SCAN events to process keys. They are to be
+used as a helper to remap keys, only. They are particularly useful when
+remapping KEY_UNKNOWN keys.
+
+The events are available in an input device, with the following id:
+
+ Bus: BUS_HOST
+ vendor: 0x1014 (PCI_VENDOR_ID_IBM) or
+ 0x17aa (PCI_VENDOR_ID_LENOVO)
+ product: 0x5054 ("TP")
+ version: 0x4101
+
+The version will have its LSB incremented if the keymap changes in a
+backwards-compatible way. The MSB shall always be 0x41 for this input
+device. If the MSB is not 0x41, do not use the device as described in
+this section, as it is either something else (e.g. another input device
+exported by a thinkpad driver, such as HDAPS) or its functionality has
+been changed in a non-backwards compatible way.
+
+Adding other event types for other functionalities shall be considered a
+backwards-compatible change for this input device.
+
+Thinkpad-acpi Hot Key event map (version 0x4101):
+
+ACPI Scan
+event code Key Notes
+
+0x1001 0x00 FN+F1 -
+0x1002 0x01 FN+F2 IBM: battery (rare)
+ Lenovo: Screen lock
+
+0x1003 0x02 FN+F3 Many IBM models always report
+ this hot key, even with hot keys
+ disabled or with Fn+F3 masked
+ off
+ IBM: screen lock
+ Lenovo: battery
+
+0x1004 0x03 FN+F4 Sleep button (ACPI sleep button
+ semanthics, i.e. sleep-to-RAM).
+ It is always generate some kind
+ of event, either the hot key
+ event or a ACPI sleep button
+ event. The firmware may
+ refuse to generate further FN+F4
+ key presses until a S3 or S4 ACPI
+ sleep cycle is performed or some
+ time passes.
+
+0x1005 0x04 FN+F5 Radio. Enables/disables
+ the internal BlueTooth hardware
+ and W-WAN card if left in control
+ of the firmware. Does not affect
+ the WLAN card.
+ Should be used to turn on/off all
+ radios (bluetooth+W-WAN+WLAN),
+ really.
+
+0x1006 0x05 FN+F6 -
+
+0x1007 0x06 FN+F7 Video output cycle.
+ Do you feel lucky today?
+
+0x1008 0x07 FN+F8 IBM: toggle screen expand
+ Lenovo: configure ultranav
+
+0x1009 0x08 FN+F9 -
+ .. .. ..
+0x100B 0x0A FN+F11 -
+
+0x100C 0x0B FN+F12 Sleep to disk. You are always
+ supposed to handle it yourself,
+ either through the ACPI event,
+ or through a hotkey event.
+ The firmware may refuse to
+ generate further FN+F4 key
+ press events until a S3 or S4
+ ACPI sleep cycle is performed,
+ or some time passes.
+
+0x100D 0x0C FN+BACKSPACE -
+0x100E 0x0D FN+INSERT -
+0x100F 0x0E FN+DELETE -
+
+0x1010 0x0F FN+HOME Brightness up. This key is
+ always handled by the firmware
+ in IBM ThinkPads, even when
+ unmasked. Just leave it alone.
+ For Lenovo ThinkPads with a new
+ BIOS, it has to be handled either
+ by the ACPI OSI, or by userspace.
+0x1011 0x10 FN+END Brightness down. See brightness
+ up for details.
+
+0x1012 0x11 FN+PGUP Thinklight toggle. This key is
+ always handled by the firmware,
+ even when unmasked.
+
+0x1013 0x12 FN+PGDOWN -
+
+0x1014 0x13 FN+SPACE Zoom key
+
+0x1015 0x14 VOLUME UP Internal mixer volume up. This
+ key is always handled by the
+ firmware, even when unmasked.
+ NOTE: Lenovo seems to be changing
+ this.
+0x1016 0x15 VOLUME DOWN Internal mixer volume up. This
+ key is always handled by the
+ firmware, even when unmasked.
+ NOTE: Lenovo seems to be changing
+ this.
+0x1017 0x16 MUTE Mute internal mixer. This
+ key is always handled by the
+ firmware, even when unmasked.
+
+0x1018 0x17 THINKPAD Thinkpad/Access IBM/Lenovo key
+
+0x1019 0x18 unknown
+.. .. ..
+0x1020 0x1F unknown
+
+The ThinkPad firmware does not allow one to differentiate when most hot
+keys are pressed or released (either that, or we don't know how to, yet).
+For these keys, the driver generates a set of events for a key press and
+immediately issues the same set of events for a key release. It is
+unknown by the driver if the ThinkPad firmware triggered these events on
+hot key press or release, but the firmware will do it for either one, not
+both.
+
+If a key is mapped to KEY_RESERVED, it generates no input events at all.
+If a key is mapped to KEY_UNKNOWN, it generates an input event that
+includes an scan code. If a key is mapped to anything else, it will
+generate input device EV_KEY events.
+
+Non hot-key ACPI HKEY event map:
+0x5001 Lid closed
+0x5002 Lid opened
+0x7000 Radio Switch may have changed state
+
+The above events are not propagated by the driver, except for legacy
+compatibility purposes when hotkey_report_mode is set to 1.
+
+Compatibility notes:
+
+ibm-acpi and thinkpad-acpi 0.15 (mainline kernels before 2.6.23) never
+supported the input layer, and sent events over the procfs ACPI event
+interface.
+
+To avoid sending duplicate events over the input layer and the ACPI
+event interface, thinkpad-acpi 0.16 implements a module parameter
+(hotkey_report_mode), and also a sysfs device attribute with the same
+name.
+
+Make no mistake here: userspace is expected to switch to using the input
+layer interface of thinkpad-acpi, together with the ACPI netlink event
+interface in kernels 2.6.23 and later, or with the ACPI procfs event
+interface in kernels 2.6.22 and earlier.
+
+If no hotkey_report_mode module parameter is specified (or it is set to
+zero), the driver defaults to mode 1 (see below), and on kernels 2.6.22
+and earlier, also allows one to change the hotkey_report_mode through
+sysfs. In kernels 2.6.23 and later, where the netlink ACPI event
+interface is available, hotkey_report_mode cannot be changed through
+sysfs (it is read-only).
+
+If the hotkey_report_mode module parameter is set to 1 or 2, it cannot
+be changed later through sysfs (any writes will return -EPERM to signal
+that hotkey_report_mode was locked. On 2.6.23 and later, where
+hotkey_report_mode cannot be changed at all, writes will return -EACES).
+
+hotkey_report_mode set to 1 makes the driver export through the procfs
+ACPI event interface all hot key presses (which are *also* sent to the
+input layer). This is a legacy compatibility behaviour, and it is also
+the default mode of operation for the driver.
+
+hotkey_report_mode set to 2 makes the driver filter out the hot key
+presses from the procfs ACPI event interface, so these events will only
+be sent through the input layer. Userspace that has been updated to use
+the thinkpad-acpi input layer interface should set hotkey_report_mode to
+2.
+
+Hot key press events are never sent to the ACPI netlink event interface.
+Really up-to-date userspace under kernel 2.6.23 and later is to use the
+netlink interface and the input layer interface, and don't bother at all
+with hotkey_report_mode.