Author: Henrique de Moraes Holschuh <[EMAIL PROTECTED]>
AuthorDate: Fri Apr 27 22:00:13 2007 -0300
Committer: Len Brown <[EMAIL PROTECTED]>
CommitDate: Sat Apr 28 21:41:19 2007 -0400
ACPI: thinkpad-acpi: improve fan control documentation
Improve fan control documentation and fix one mistake.
Signed-off-by: Henrique de Moraes Holschuh <[EMAIL PROTECTED]>
Signed-off-by: Len Brown <[EMAIL PROTECTED]>
Documentation/thinkpad-acpi.txt | 18 +++++++++++++-----
1 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/Documentation/thinkpad-acpi.txt b/Documentation/thinkpad-acpi.txt
index bca50d7..e3ad7a4 100644
@@ -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
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