further to my email yesterday (to which i've had no response :) i 
propose the attached patch to arch/i386/kernel/irq.c. it corrects what i 
see as a bug in interrupt handling.

currently if a driver requests SA_INTERRUPT in an interrupt handler, it 
is only called with interrupts disabled if it is the first handler in 
the list.

my patch modifies setup_irq to put any interrupt with SA_INTERRUPT in 
the front of the handler queue (eg before any handlers without the flag).

and also modifies handle_IRQ_event to only enable interrupts when it 
hits the first handler with SA_INTERRUPT not set.

the patch is against 2.5.62 and greatly improves stability on my SMP system.

james