On Sat, 20 Oct 2007, Maxim Levitsky wrote:
>
> and the interrupt handler:
>
> smp_rmb();
> if (dev->insuspend)
> goto out;
Something like that can work, yes. However, you need to make sure that:
- even when you ignore the interrupt (because the driver doesn't care,
it's suspending), you need to make sure the hardware gets shut up by
reading (or writing) the proper interrupt status register.
Otherwise, with a level interrupt, the interrupt will continue to be
held active ("screaming") and the CPU will get interrupted over and
over again, until the irq subsystem will just turn the irq off
entirely.
- when you resume, make sure that you get the engine going again, with
the understanding that some interrupts may have gotten ignored.
Also, in general, these kinds of things shouldn't always even be
neicessary. If you use the suspend_late()/resume_early() hooks, those will
be called with interrupts off, and while they can be harder to debug (and
may be worth avoiding for non-critical drivers), they do allow for simpler
models partly exactly because they don't need to worry about interrupts
etc.
Linus
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