From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Sat, 29 Nov 2008 11:08:37 +0100
From: Marco Cavallini <koansoftware@domain.hid>
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Subject: Re: [Xenomai-help] NETDEV WATCHDOG on ARM
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To: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Cc: Xenomai help <xenomai@xenomai.org>

Gilles Chanteperdrix ha scritto:
> Stefano Gafforelli wrote:
>> With additional patch...do you think that the problem is due to the relation
>> between additional patch and xenomai?
> 
> Yes, that is something possible. Normally, we try to test that Xenomai
> is compatible with the AT91 patch, but some error may escape, and we
> never tested the ronetix patch, which I do not know. So, please test
> without these additional patches.
> 
> P.S: please always CC the mailing list.
> 

Working with Stefano we pointed out some issues.

1. we successfully build linux-2.6.26 with xenomai-2.4.6.1 adding a
little patch.
2. we tested it on an AT91SAM9261 board and noticed that latency freezes
at "warming up..."
3. so we returned to the 'stable' linux-2.6.25 with xenomai-2.4.4
4. testing latency with this version succeeded
5. unfortunately network is not working so after debugging Stefano
dicovered that executing irq_finish(irq) in asm_do_IRQ()
[arch/arm/kernel/irq.c] made network working.


asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs
*regs)
{
        struct pt_regs *old_regs = set_irq_regs(regs);
        struct irq_desc *desc = irq_desc + irq;

        /*
         * Some hardware gives randomly wrong interrupts.  Rather
         * than crashing, do something sensible.
         */
        if (irq >= NR_IRQS)
                desc = &bad_irq_desc;

        irq_enter();

        desc_handle_irq(irq, desc);

//#ifndef CONFIG_IPIPE
        /* AT91 specific workaround */
        irq_finish(irq);
//#endif /* !CONFIG_IPIPE */

        irq_exit();
        set_irq_regs(old_regs);
}


We wonder why irq_finish() is not executed here when using IPIPE mode in
this asm_do_IRQ(().

Any hint will be greatly appreciated :-)


/marco & stefano