On Mon, Nov 02, 2009 at 05:47:57PM +0100, Nicolas Ferre wrote:

in arch/arm/mach-at91/at91sam926x_time.c +125
 .flags = IRQF_SHARED | IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,

IRQF_DISABLED is positionned. But on the other hand, I saw in the kernel
booting messages that:
"IRQ 1/rtc0: IRQF_DISABLED is not guaranteed on shared IRQs"

What does this mean ? what is the difference with former way of managing
shared interrupts ?

If the first IRQ action which is run was registered without IRQF_DISABLED
the entire set will be run without interrupts disabled.

And above all, what is the proper way to set an IRQ on a shared
interrupt line ?

The only real solution is to ensure that all requesters use IRQF_DISABLED.