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-rw-r--r--Documentation/laptops/thinkpad-acpi.txt47
1 files changed, 41 insertions, 6 deletions
diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index af1f2bcb6f66..73b80a7e9b03 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -876,28 +876,63 @@ The cmos command interface is prone to firmware split-brain problems, as
876in newer ThinkPads it is just a compatibility layer. Do not use it, it is 876in newer ThinkPads it is just a compatibility layer. Do not use it, it is
877exported just as a debug tool. 877exported just as a debug tool.
878 878
879LED control -- /proc/acpi/ibm/led 879LED control
880--------------------------------- 880-----------
881 881
882Some of the LED indicators can be controlled through this feature. The 882procfs: /proc/acpi/ibm/led
883available commands are: 883sysfs attributes: as per led class, see below for names
884
885Some of the LED indicators can be controlled through this feature. On
886some older ThinkPad models, it is possible to query the status of the
887LED indicators as well. Newer ThinkPads cannot query the real status
888of the LED indicators.
889
890procfs notes:
891
892The available commands are:
884 893
885 echo '<led number> on' >/proc/acpi/ibm/led 894 echo '<led number> on' >/proc/acpi/ibm/led
886 echo '<led number> off' >/proc/acpi/ibm/led 895 echo '<led number> off' >/proc/acpi/ibm/led
887 echo '<led number> blink' >/proc/acpi/ibm/led 896 echo '<led number> blink' >/proc/acpi/ibm/led
888 897
889The <led number> range is 0 to 7. The set of LEDs that can be 898The <led number> range is 0 to 7. The set of LEDs that can be
890controlled varies from model to model. Here is the mapping on the X40: 899controlled varies from model to model. Here is the common ThinkPad
900mapping:
891 901
892 0 - power 902 0 - power
893 1 - battery (orange) 903 1 - battery (orange)
894 2 - battery (green) 904 2 - battery (green)
895 3 - UltraBase 905 3 - UltraBase/dock
896 4 - UltraBay 906 4 - UltraBay
907 5 - UltraBase battery slot
908 6 - (unknown)
897 7 - standby 909 7 - standby
898 910
899All of the above can be turned on and off and can be made to blink. 911All of the above can be turned on and off and can be made to blink.
900 912
913sysfs notes:
914
915The ThinkPad LED sysfs interface is described in detail by the led class
916documentation, in Documentation/leds-class.txt.
917
918The leds are named (in LED ID order, from 0 to 7):
919"tpacpi::power", "tpacpi:orange:batt", "tpacpi:green:batt",
920"tpacpi::dock_active", "tpacpi::bay_active", "tpacpi::dock_batt",
921"tpacpi::unknown_led", "tpacpi::standby".
922
923Due to limitations in the sysfs led class, if the status of the LED
924indicators cannot be read due to an error, thinkpad-acpi will report it as
925a brightness of zero (same as LED off).
926
927If the thinkpad firmware doesn't support reading the current status,
928trying to read the current LED brightness will just return whatever
929brightness was last written to that attribute.
930
931These LEDs can blink using hardware acceleration. To request that a
932ThinkPad indicator LED should blink in hardware accelerated mode, use the
933"timer" trigger, and leave the delay_on and delay_off parameters set to
934zero (to request hardware acceleration autodetection).
935
901ACPI sounds -- /proc/acpi/ibm/beep 936ACPI sounds -- /proc/acpi/ibm/beep
902---------------------------------- 937----------------------------------
903 938