LED indicators as well. Newer ThinkPads cannot query the real status
of the LED indicators.
+Because misuse of the LEDs could induce an unaware user to perform
+dangerous actions (like undocking or ejecting a bay device while the
+buses are still active), or mask an important alarm (such as a nearly
+empty battery, or a broken battery), access to most LEDs is
+restricted.
+
+Unrestricted access to all LEDs requires that thinkpad-acpi be
+compiled with the CONFIG_THINKPAD_ACPI_UNSAFE_LEDS option enabled.
+Distributions must never enable this option. Individual users that
+are aware of the consequences are welcome to enabling it.
+
procfs notes:
The available commands are:
from 0 to 15.
There are two interfaces to the firmware for direct brightness control,
-EC and CMOS. To select which one should be used, use the
+EC and UCMS (or CMOS). To select which one should be used, use the
brightness_mode module parameter: brightness_mode=1 selects EC mode,
-brightness_mode=2 selects CMOS mode, brightness_mode=3 selects both EC
-and CMOS. The driver tries to auto-detect which interface to use.
+brightness_mode=2 selects UCMS mode, brightness_mode=3 selects EC
+mode with NVRAM backing (so that brightness changes are remembered
+across shutdown/reboot).
+
+The driver tries to select which interface to use from a table of
+defaults for each ThinkPad model. If it makes a wrong choice, please
+report this as a bug, so that we can fix it.
When display backlight brightness controls are available through the
standard ACPI interface, it is best to use it instead of this direct
accessing some functions of the driver
0x0001 Initialization and probing
0x0002 Removal
+ 0x0004 RF Transmitter control (RFKILL)
+ (bluetooth, WWAN, UWB...)
+ 0x0008 HKEY event interface, hotkeys
+ 0x0010 Fan control
+ 0x0020 Backlight brightness
There is also a kernel build option to enable more debugging
information, which may be necessary to debug driver problems.