Revert the backout in the last revision, it was committed to the wrong branch.

Pointy hat to:  brueffer

1 files changed, 22 insertions, 2 deletions

diff --git a/share/man/man4/man4.i386/acpi_ibm.4 b/share/man/man4/man4.i386/acpi_ibm.4
index 4375e41..c89201e 100644
--- a/share/man/man4/man4.i386/acpi_ibm.4
+++ b/share/man/man4/man4.i386/acpi_ibm.4
@@ -281,8 +281,28 @@ Toggle Bluetooth chip activity.
 (read-only)
 Indicates whether the WLAN chip is active or not.
 .It Va dev.acpi_ibm.0.fan
-(read-only)
-Indicates whether the fan is on or off.
+Indicates whether the fan is in automatic (1) or manual (0) mode.
+Default is automatic mode.
+This sysctl should be used with extreme precaution, since disabling automatic
+fan control might overheat the ThinkPad and lead to permanent damage if the
+.Va fan_level
+is not set accordingly.
+.It Va dev.acpi_ibm.0.fan_level
+Indicates at what speed the fan should run when being in manual mode.
+Values are ranging from 0 (off) to 7 (max).
+The resulting speed differs from model to model.
+On a T41p this is as follows:
+.Pp
+.Bl -tag -width indent-two -compact
+.It Li 0
+off
+.It Li 1, 2
+~3000 RPM
+.It Li 3, 4, 5
+~3600 RPM
+.It Li 6, 7
+~4300 RPM
+.El
 .It Va dev.acpi_ibm.0.fan_speed
 (read-only)
 Fan speed in rounds per minute.