.TH "BREEZED" "1.4" "Mar 2010" "Francois Fleuret" "System Deamons"
.SH "NAME"
breezed - Fan control daemon
.SH "SYNOPSIS"
.PP
\fBbreezed\fP [\fBoptions\fP]
.SH "DESCRIPTION"
.PP
\fBbreezed\fP is a daemon to adjust the fan speed according to the
computer temperature. It should be started through the adequate
systemd configuration or script in /etc/rc?.d.

Every 5s, \fBbreezed\fP gathers all integer values from the thermal
files, and takes the max as the overall temperature T. It then
computes the highest fan speed whose temperature threshold is lower
than T. If that speed is above the current speed, the daemon changes
the fan speed accordingly. Otherwise it computes the lowest fan speed
whose temperature threshold is two degrees above T, and sets the fan
speed one level below. This two degree gap avoids too many
oscillations. Also, the daemon waits for at least 30s after any change
of the fan speed before reducing it. The fan speed is set by writing
"level <speed_name>" into the specified fan file. The speed name is
the level itself if no alternative is provided with the temperature
threshold.

Options cannot be specified twice, neither on the command line nor in
the configuration file.

.SH "OPTIONS"
.IP "\fB-h | --help\fP" 10
display help and exits
.IP "\fB-v | --version\fP" 10
display the version number and exits
.IP "\fB-d | --debug\fP" 10
run in verbose mode
.IP "\fB-cf | --configuration-file <file>\fP" 10
set the configuration file (default is /etc/breezed.conf)
.IP "\fB-ncf | --no-configuration-file\fP" 10
prevent the reading of a configuration file
.IP "\fB-tf | --thermal-file <file1>[,file2]...\fP" 10
set the files to spool for temperatures.
.IP "\fB-ff | --fan-file <file>\fP" 10
set the file to control the fan speed.
.IP "\fB-tt | --temperature-thresholds <temp1>[:<speed_name_1>][,temp2[:speed_name_2]]...\fP" 10
set the temperature thresholds.

.SH "CONFIGURATION FILE"

The configuration file is a succession of lines, each starting with
one of the three keywords thermal_files, fan_file or
temperature_thresholds, followed by the same parameter values as for
the command line arguments. The default configuration file is located
at /etc/breezed.conf

.SH "EXAMPLES"

If a configuration file exists, the standard way to start breezed is
to run it without arguments.

Starting it with all the arguments on the commande line can be done
for instance with

.P
.nf
.B breezed --no-configuration-file \e
.B \ \ \ \ \ \ \ \ --thermal-files /proc/acpi/thermal_zone/THM0/temperature,/proc/acpi/thermal_zone/THM1/temperature \e
.B \ \ \ \ \ \ \ \ --fan-file /proc/acpi/ibm/fan \e
.B \ \ \ \ \ \ \ \ --temperature-thresholds 52,54,56,58,60,62,64,68:full-speed

which specifies that when the temperature raises above 52C, the fan
level should be 1, when the temperature raises above 54C it should be
2, etc. The maximum speed level 8 should be chosen for temperatures
above 68C, and its name is "full-speed" (since no other speed name is
provided, the other ones are the default level names, hence their
numerical value).

Due to the two degrees gap between the thresholds to increase and the
thresholds to decrease the temperature, it will for instance remains
at speed 1 until the temperature goes down to 50C.

Because it takes into account all the values found in the thermal
files, you can use as well /proc/acpi/thermal_zone/THM?/temperature or
/proc/acpi/ibm/thermal.

.SH "AUTHOR"
.PP
Written by Francois Fleuret <francois@fleuret.org>. Permission is
granted to copy, distribute and/or modify this document under the
terms of the GNU GPL.