Re: RT_PREEMPT problem with cascaded irqchip

[Yann . LEPROVOST]

Well, in fact the issue doesn't come neither from the mask/unmask procedure
nor from the set_irq calls.
Correct gpio mask/unmask are called before the gpio_irq_handler.

However, there is an issue in gpio_irq_handler (specific to generic_irq and
AT91RM9200, i think) concerning desc->chip->chip_data.
The following change has to be applied :

 --    pio = (void __force __iomem *) desc->chip->chip_data;
++   pio = (void __force __iomem *) desc->chip_data;

Moreover, I think that the call to redirect_hardirq have to be insered in
gpio_irq_handler but I don't know how to do that.

Regards

Yann Leprovost



                                                                           
             Thomas Gleixner                                               
             <tglx@linutronix.                                             
             de>                                                        To 
             Sent by:                  Yann.LEPROVOST@xxxxxxxxxx           
             linux-kernel-owne                                          cc 
             r@xxxxxxxxxxxxxxx         Daniel Walker <dwalker@xxxxxxxxxx>, 
                                       linux-kernel@xxxxxxxxxxxxxxx,       
                                       linux-kernel-owner@xxxxxxxxxxxxxxx, 
             30/05/2006 13:22          Ingo Molnar <mingo@xxxxxxx>, Steven 
                                       Rostedt <rostedt@xxxxxxxxxxx>,      
                                       Esben Nielsen <simlo@xxxxxxxxxx>,   
             Please respond to         Sven-Thorsten Dietrich              
             tglx@xxxxxxxxxxxx         <sven@xxxxxxxxxx>                   
                     e                                             Subject 
                                       Re: RT_PREEMPT problem with         
                                       cascaded irqchip                    
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




On Tue, 2006-05-30 at 12:26 +0200, Yann.LEPROVOST@xxxxxxxxxx wrote:
> Of course, here is the file arch/arm/mach-at91rm9200/gpio.c with my
> modified gpio_irq_handler.

>             for (i = 0; i < 32; i++, pin++) {
>                   set_irq_chip(pin, &gpio_irqchip);
>                         printk(KERN_ERR "GPIO SET_IRQ_CHIP\n");
>                   set_irq_handler(pin, do_simple_IRQ);

-----------------------------------------^^^^^^^^^^^^^^^

Care to look into the implementation of this ? As the name says, its
simple. It does no ack/mask whatever. Use the level resp. the edge
handler instead.

             tglx




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