hello,

I'm new to the driver programming. i successfully compiled kernel source 2.6.18 and i'm running it. the simple driver program what i wrote successfully compiled and i got .ko module. but as do insmod mymodule.ko i could see nothing on the screen, just root# prompt. what could be the reason? help me.
this is simple program i wrote:

#include<linux/init.h>
#include<linux/module.h>
MODULE_LICENSE("Dual BSD/GPL");
int init_module(void){
printk("<1>Hello World\n");
return 0;
}
void cleanup_module(void){
printk("<1>Good BYE\n");
}

and i compiled as
root# make -C "lib/modules/$(uname -r)/build" M=$PWD obj-m="$(basename mymodule.c .c).o"

i got mymodule.ko ,these are steps i followed to load module and results i got are as below
root#insmod ./mymodule.ko
root#
root#rmmod mymodule
root#
i could see no print messages on the screen. what the problem here? but the module is loaded, i checked using lsmod and in /proc/modules

I've not done any kernel programming, but could it be that the output isn't meant to be shown on the terminal and appears in /var/log/messages or something else?

Thanks for the reply..
It is in /var/log/messages.. but how to get it printed on the konsole? reply please..

You want to use printk for debugging?? thats way you want it on console. right?

you could just do the tail -n [any number] on /var/log/messages to se the values at some critical point.

As far as remember printing message only help so much.

Messages won't show up if you are running under X (i.e. gnome or KDE + xterm). If you use Gnome, Control+Alt+F1 will put you into the first console. Login as root, then do the insmod and rmmod.

Thanks sixerjman.. now i am able debug my module..