diff options
-rw-r--r-- | 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 bca50d78a425..e3ad7a4f7402 100644 --- a/Documentation/thinkpad-acpi.txt +++ b/Documentation/thinkpad-acpi.txt | |||
@@ -795,15 +795,23 @@ Sysfs notes: | |||
795 | The sysfs interface follows the hwmon subsystem guidelines for the most | 795 | The sysfs interface follows the hwmon subsystem guidelines for the most |
796 | part, and the exception is the fan safety watchdog. | 796 | part, and the exception is the fan safety watchdog. |
797 | 797 | ||
798 | Writes to any of the sysfs attributes may return the EINVAL error if | ||
799 | that operation is not supported in a given ThinkPad or if the parameter | ||
800 | is out-of-bounds, and EPERM if it is forbidden. They may also return | ||
801 | EINTR (interrupted system call), and EIO (I/O error while trying to talk | ||
802 | to the firmware). | ||
803 | |||
804 | Features not yet implemented by the driver return ENOSYS. | ||
805 | |||
798 | hwmon device attribute pwm1_enable: | 806 | hwmon 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 | ||
808 | hwmon device attribute pwm1: | 816 | hwmon 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: | |||
826 | To stop the fan: set pwm1 to zero, and pwm1_enable to 1. | 834 | To stop the fan: set pwm1 to zero, and pwm1_enable to 1. |
827 | 835 | ||
828 | To start the fan in a safe mode: set pwm1_enable to 2. If that fails | 836 | To start the fan in a safe mode: set pwm1_enable to 2. If that fails |
829 | with ENOTSUP, set it to 1 and set pwm1 to at least 128 (255 would be the | 837 | with EINVAL, try to set pwm1_enable to 1 and pwm1 to at least 128 (255 |
830 | safest choice, though). | 838 | would be the safest choice, though). |
831 | 839 | ||
832 | 840 | ||
833 | EXPERIMENTAL: WAN -- /proc/acpi/ibm/wan | 841 | EXPERIMENTAL: WAN -- /proc/acpi/ibm/wan |