[PATCH 5/9] ACPI: thinkpad-acpi: improve fan control documentation

Henrique de Moraes Holschuh
2007-04-28T01:00:13Z

Improve fan control documentation and fix one mistake.

Signed-off-by: Henrique de Moraes Holschuh <hmh-N3TV7GIv+o9fyO9Q7EP/yw@public.gmane.org>
---
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
--- a/Documentation/thinkpad-acpi.txt
+++ b/Documentation/thinkpad-acpi.txt
@@ -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
--
1.5.1

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