On Mon, 2003-02-03 at 21:31, Ralph Siemsen wrote:
> How about the next best thing: a silent machine that turns on its fan
> if it is about to overheat? I can make my binary available if wanted.
> ftp://ftp.netwinder.org/users/g/guinan/fand.c
I had some problems with the original fand.c so I rewrote it. I've
attached my version to this message.
--
------------ Alex Holden - http://www.linuxhacker.org ------------
If it doesn't work, you're not hitting it with a big enough hammer
/*
* Jamie Guinan, December 1998
* Tidied up somewhat by Alex Holden, January 2001.
*
* Turns the fan off when the temperature gets down to two degrees below the
* low thermostat setting, and turns it back on again when it reaches the
* low setting. This gives a two degree hysteresis band, which seems to give
* good results for me. Changes to the thermostat settings are automatically
* detected, and the fan is always turned back on again on exit except when
* kill -9'ed.
*
* Copyright: Free for redistribution, modifications welcome, as
* long as credits maintained.
*
* Warranty: None whatsoever.
*/
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <asm/therm.h>
#define THERMDEV "/dev/temperature"
int therm_fd;
void set_fan(int i) { ioctl(therm_fd, CMD_SET_FAN, &i); }
/* On exit, turn the fan on first. */
void exit_handler(void) { set_fan(1); }
void daemonise()
{
switch(fork()) {
case 0: /* Child. */
break;
case -1: /* Error. */
exit(1);
break;
default: /* Parent. */
exit(0);
}
/* No controlling terminal. */
setsid();
}
void initialise(void)
{
/* Go into background */
daemonise();
/* Open the thermostat device. */
if((therm_fd = open(THERMDEV, O_RDONLY)) == -1) exit(1);
/* Make sure we turn the fan back on on exit. */
atexit(exit_handler);
}
int main(int argc, char *argv[])
{
struct therm ts;
int temp;
/* Initialise the program */
initialise();
/* Main loop */
while(1) {
/* Get the current temperature */
ioctl(therm_fd, CMD_GET_TEMPERATURE, &temp);
/* Get the current thermostat settings */
ioctl(therm_fd, CMD_GET_THERMOSTATE2, &ts);
/* Turn the fan off if we are 2 degrees below the low setting */
if(temp <= (ts.lo - 2)) set_fan(0);
/* Turn the fan on if we are at or above the low setting */
else if(temp >= ts.lo) set_fan(1);
/* Wait a second between each reading */
sleep(1);
}
return 0;
}
