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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>
hifive-unleashed-5.1
Henrique de Moraes Holschuh 2007-04-27 22:00:13 -03:00 committed by Len Brown
parent c573ddb998
commit b39fe582eb
1 changed files with 13 additions and 5 deletions
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18
Documentation/thinkpad-acpi.txt
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@ -795,15 +795,23 @@ Sysfs notes:
The sysfs interface follows the hwmon subsystem guidelines for the most
part, and the exception is the fan safety watchdog.
Writes to any of the sysfs attributes may return the EINVAL error if
that operation is not supported in a given ThinkPad or if the parameter
is out-of-bounds, and EPERM if it is forbidden. They may also return
EINTR (interrupted system call), and EIO (I/O error while trying to talk
to the firmware).
Features not yet implemented by the driver return ENOSYS.
hwmon device attribute pwm1_enable:
0: PWM offline (fan is set to full-speed mode)
1: Manual PWM control (use pwm1 to set fan level)
2: Hardware PWM control (EC "auto" mode)
3: reserved (Software PWM control, not implemented yet)
Modes 0 and 2 are not supported by all ThinkPads, and the driver
is not always able to detect this. If it does know a mode is
unsupported, it will return -EINVAL.
Modes 0 and 2 are not supported by all ThinkPads, and the
driver is not always able to detect this. If it does know a
mode is unsupported, it will return -EINVAL.
hwmon device attribute pwm1:
Fan level, scaled from the firmware values of 0-7 to the hwmon
@ -826,8 +834,8 @@ driver attribute fan_watchdog:
To stop the fan: set pwm1 to zero, and pwm1_enable to 1.
To start the fan in a safe mode: set pwm1_enable to 2. If that fails
with ENOTSUP, set it to 1 and set pwm1 to at least 128 (255 would be the
safest choice, though).
with EINVAL, try to set pwm1_enable to 1 and pwm1 to at least 128 (255
would be the safest choice, though).
EXPERIMENTAL: WAN -- /proc/acpi/ibm/wan