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authorHenrique de Moraes Holschuh <hmh@hmh.eng.br>2007-04-27 21:00:13 -0400
committerLen Brown <len.brown@intel.com>2007-04-28 21:41:19 -0400
commitb39fe582eb9252dca9a62f7135bcad2e486083e5 (patch)
tree597cc56e18c4fe628d99c6f1c9d7470126d50dc7
parentc573ddb998456a89a5ccb83a922d2c8ba18484a6 (diff)
ACPI: thinkpad-acpi: improve fan control documentation
Improve fan control documentation and fix one mistake. Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Signed-off-by: Len Brown <len.brown@intel.com>
-rw-r--r--Documentation/thinkpad-acpi.txt18
1 files changed, 13 insertions, 5 deletions
diff --git a/Documentation/thinkpad-acpi.txt b/Documentation/thinkpad-acpi.txt
index bca50d78a425..e3ad7a4f7402 100644
--- a/Documentation/thinkpad-acpi.txt
+++ b/Documentation/thinkpad-acpi.txt
@@ -795,15 +795,23 @@ Sysfs notes:
795The sysfs interface follows the hwmon subsystem guidelines for the most 795The sysfs interface follows the hwmon subsystem guidelines for the most
796part, and the exception is the fan safety watchdog. 796part, and the exception is the fan safety watchdog.
797 797
798Writes to any of the sysfs attributes may return the EINVAL error if
799that operation is not supported in a given ThinkPad or if the parameter
800is out-of-bounds, and EPERM if it is forbidden. They may also return
801EINTR (interrupted system call), and EIO (I/O error while trying to talk
802to the firmware).
803
804Features not yet implemented by the driver return ENOSYS.
805
798hwmon device attribute pwm1_enable: 806hwmon device attribute pwm1_enable:
799 0: PWM offline (fan is set to full-speed mode) 807 0: PWM offline (fan is set to full-speed mode)
800 1: Manual PWM control (use pwm1 to set fan level) 808 1: Manual PWM control (use pwm1 to set fan level)
801 2: Hardware PWM control (EC "auto" mode) 809 2: Hardware PWM control (EC "auto" mode)
802 3: reserved (Software PWM control, not implemented yet) 810 3: reserved (Software PWM control, not implemented yet)
803 811
804 Modes 0 and 2 are not supported by all ThinkPads, and the driver 812 Modes 0 and 2 are not supported by all ThinkPads, and the
805 is not always able to detect this. If it does know a mode is 813 driver is not always able to detect this. If it does know a
806 unsupported, it will return -EINVAL. 814 mode is unsupported, it will return -EINVAL.
807 815
808hwmon device attribute pwm1: 816hwmon device attribute pwm1:
809 Fan level, scaled from the firmware values of 0-7 to the hwmon 817 Fan level, scaled from the firmware values of 0-7 to the hwmon
@@ -826,8 +834,8 @@ driver attribute fan_watchdog:
826To stop the fan: set pwm1 to zero, and pwm1_enable to 1. 834To stop the fan: set pwm1 to zero, and pwm1_enable to 1.
827 835
828To start the fan in a safe mode: set pwm1_enable to 2. If that fails 836To start the fan in a safe mode: set pwm1_enable to 2. If that fails
829with ENOTSUP, set it to 1 and set pwm1 to at least 128 (255 would be the 837with EINVAL, try to set pwm1_enable to 1 and pwm1 to at least 128 (255
830safest choice, though). 838would be the safest choice, though).
831 839
832 840
833EXPERIMENTAL: WAN -- /proc/acpi/ibm/wan 841EXPERIMENTAL: WAN -- /proc/acpi/ibm/wan