Hi all, I have been working on this following problem for a while and I'm getting nowhere.
I am using single-board computer (SBC) running White Dwarf Linux v2.0 with the following details:
Kernel: v2.4.20 White Dwarf Linux: v2.0 gnu: v3.3
I have written a kernel module to react on an external hardware interrupt that will occur at e.g. IRQ 7 line. The idea is then my application code could wait for an interrupt (perform an ioctl(WAIT_ON_INTERRUPT)) and react to it.
The basic structure of this module is given below:
MyModule.o
------------------
wait_queue_head_t int_queue;
__init initModule() { ?.. proper initialization, etc ?.
//register the interrupt handler request_irq(IRQ7,myHndlr, PORTNAME,NULL) //initialize the queue head init_waitqueue_head(&int_queue); }
myHndlr() { //re-wake the interrupt if asleep wake_up_interruptible(&int_queue); }
myIoclt() { //re-init the queue head init_waitqueue_head(&int_queue); //now wait for the interrupt interruptible_sleep_on(&int_queue); }
And I compiled this module using proper flags such as _MODULE _KERNEL etc....
I know the above module coupled with my application worked very well with kernel 2.2.20.
PROBLEM
------- When I recently moved to kernel 2.4.20, I get a kernel panic (Oops screen dump) every time I get the interrupt occurring. Hence, when interrupt occurs the trace jumps to myHndlr() and kernel panic occurs at the point of wake_up_interruptible(&int_queue);
What could this be?
Why did the identical module worked for 2.2.20 and not for 2.4.20?? (I made sure I used the proper lib for 2.4.20 when compiling the MyModule.o)
I have noticed slight variation of the code in /kermel/sched.c between
2.2.20 & 2.4.20, where these functions wake_up_interruptible() etc) are defined.Could it also be as a result of implementation of softirq functions. Should I enable Softirq?
I tried using cpu_raise_softirq() within MyModule.o. The module compiled correct but when I load into the kernel, I get a lot of unresolved symbols. What about ksoftirqd_CPU0, is this interfering with the system?
Any help in this matter is appreciated.
Regards, Nejhdeh Ghevondian