Kereoz

#include <stdio.h>
#include <sys/types.h>
#include <machine/pio.h>
#include <machine/sysarch.h>
#include <err.h>

int main(){
u_long iomap[32];
u_long mask = 0xFFFFFFFF;
int i = 0;

if (i386_get_ioperm(iomap) < 0) 
	errx(1,"get_ioperm failed :(");

for (i=0;i<32;i++){
iomap[i] = mask | iomap[i];
}

if (i386_set_ioperm(iomap) < 0)
errx(1, "i386_set_ioperm failed");

outb(0x03, 0xB3);
outb(0xBF, 0xB2);
char c = inb(0xb3);  
printf("%x\n",c);

// value -> addr
// backlight value (tested 0x54, 0x74, 0xA4) 
outb(0x04, 0xB3);

// ?
outb(0xBF, 0xB2);

return 0;
}