[PATCH] qe_ic: Do a sync when masking interrupts.

[Segher Boessenkool]

>> If a sync after an MMIO write is enough, then (in almost all
>> cases) so is an eieio.
>
> In this case, the spurious interrupts still happen with eieio, but  
> not with sync.  It's probably synchronizing the MMIO write with  
> some unrelated load from memory (such as reading the stack frame to  
> return from the mask function, or reading action->flags to  
> determine whether to check for IRQ_DISABLED).

Yes, it sure sounds like the only reason the sync insn helps
is that it causes a (small) delay.  If you document this (and
also that it isn't required for correctness) in the code, I
don't think anyone will complain / be curious about it anymore.


Segher