Re: [rtl] Trying To Use "request_RTirq"

[Kai Mueller <mueller@leo.ifr.ing.tu-bs.de>]

On Mon, Jun 08, 1998 at 07:56:34AM -0400, Donald Radke wrote:
> The code below is a modified version of "rt_process.c" found in the 2tasks
> example.  I have the orginal 2task working but am curious about using an
> interrupt instead.  From what I read about "request_RTirq" and "free_RTirq"
> the below program should send a message to the FIFO everytime the timer
> interrupt goes off.  Doesn't seem to do that though.  Nothing happens than
> the linux task (app.c) ends.
> 
> I tried changing timer_irq value to 1 (keyboard) and I'll receive the data
> message just after hitting the return key on the prompt line.  But no matter
> how many times I hit the keyboard, nothing comes back from the RT-Task.
> 
> I understand "request_RTirq" to work as follows:
> 
>     request_RTirq ( monitor_irq, execute_some_func );
> 
> Whenever the monitor_irq (whichever one I want) goes off, perform the
> function (ie execute_some_func).  I'm I wrong, or is there something else
> that needs to be setup???
> 
> Donald Radke
> 


Perhaps you find some recommendation useful:

1. Don't use interrupts for RT-Linux that Linux need for proper
   operations (like the keyboard interrupt). I guess it is hard
   to figure out what will happen.


> /*  Actual function to handle output  */
> void irq_handler (  )
> {
>   int     i;
> 
>   for ( i = 0; i < 1024; i++ )
>   {
>     data[i] = 'R';
>   }


2. Don't do initializations in ISR. Send a few bytes; not kilobytes
   for test purposes. 

> 
>   rtf_put ( fifo
>           , &data
>           , 1024
>           );
> 
>   return;


3. fifo seems to be not known here???

4. &data is a pointer to an array. Does not make much sense and is
   ignored by most compilers.


> 
> }     /*  End Of irq_handler  */
> 
> 
> int main_handler ( unsigned int fifo )
> {
>   struct    my_msg_struct     msg;
>   int       err;
>   int       timer_irq = 0;         /*  Set to timer interrupt  */
> 
>   while ((err = rtf_get(3, &msg, sizeof(msg))) == sizeof(msg))
>   {
>     switch (msg.command)
>     {
>       case START_TASK:
>            request_RTirq ( timer_irq, &irq_handler );

5. &irq_handler, like 4.


-- 
 Kai P. Mueller
 Control Department (Regelungstechnik) | Phone [+49] (531) 391-3835
 Technical University Braunschweig     | Fax   [+49] (531) 391-5194
 D-38092 Braunschweig                  | Email mueller@ifr.ing.tu-bs.de
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