printk is not my friend

[Charles Brown]

my problem seems to be a Makefile issue.  Following LDD3, i had started 
a char driver file (cdev.c), which i planned to add to hello.c, and i'd 
done this in the makefile;

ifneq ($(KERNELRELEASE),)
     obj-m := hello.o
     hello-objs := cdev.o

if i take out that 'cdev.o' it works.  I re-read that section of LDD3, 
"If, instead, you have a module called module.ko that is generated from 
two source files (called, say, file1.c and file2.c), the correct 
incantation would be:

obj-m := module.o
module-objs := file1.o file2.o

So, i tried this;

ifneq ($(KERNELRELEASE),)
     obj-m := module.o
     hello-objs := hello.o cdev.o

but make says, "No rule to make diver.c".

--CB


manoj.iyer at canonical.com wrote:
> 
> So if you ran dmesg it shows you nothing as well?
> 
> On Mon, 5 Apr 2010, Charles Brown wrote:
> 
>  > i'm sorry to bother you with this, but i've been chasing my tail through
>  > LDD3 and forum posts for hours with no luck, so i figure ask some
>  > experts. i have a typical 'hello world' module, on off-the-shelf ubuntu
>  > karmic, and can not get it to printk anything, anywhere, anyhow. i
>  > assume my problem is trivial, but i can't find it.  i've tried;
>  >
>  > static int __init init(void) {
>  >     printk(KERN_DEBUG "Hello, world\n");
>  > }
>  > module_init(init);
>  >
>  > static void __exit exit(void) {
>  >     printk(KERN_DEBUG "Goodbye, cruel world\n");
>  > }
>  > module_exit(exit);
>  >
>  >
>  >
>  > apt-get install klogd,
>  > echo 7 > /proc/sys/kernel/printk
>  > /etc/init.d/sysklogd restart
>  >
>  > every flavor of printk(KERN_DEBUG/CRIT/EMERG/INFO/ALERT
>  >
>  > and more things from various forums posts
>  >
>  > all the while with a tail -f /var/log/kern.log running.
>  >
>  > is there a step-by-step for 'hello world' someplace? suggestions?
>  >
>  > --CB
>  > -
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