Re: [PATCH 2/2] chipidea: Use devm_request_irq()

From: Peter Chen
Date: Wed Jul 31 2013 - 09:55:51 EST

On Wed, Jul 31, 2013 at 9:27 PM, Mark Brown <broonie@xxxxxxxxxx> wrote:
> On Wed, Jul 31, 2013 at 07:55:27AM -0400, Tejun Heo wrote:
>> If you have DMA / IRQ / command engine deactivations in devm path
>> which often is the case with full conversions, freeing any resources
>> including DMA areas and host private data in the wrong order is a
>> horrible idea. It's worse as it won't really be noticeable in most
>> cases.
> It's really only interrupts that affect most devices - if there's DMA or
> anything going on after the remove() then as you said earlier the driver
> is probably doing something wrong.

I think the main point is we should allocate managed resource which is used
at interrupt handler before devm_request_irq, and all resources used
at interrupt
handler should be managed.

If we use non-managed resource at interrupt handler, but using managed interrupt
handler, things still will go wrong if there is an odd (unexpected)
interrupt after
we finish deactivation at removal.

Peter Chen
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