Re: contention on long-held spinlock

[Arnd Bergmann]

On Friday 19 August 2011, Bryan Donlan wrote:
> That's what mutexes are for. Note, however, that interrupt handlers
> cannot use mutexes as they cannot sleep, nor can they wait for lock
> holders which may themselves sleep.

I agree that there is probably some other bug that needs to be fixed
in the driver, but for testing it may well be worth replacing
the spinlock with a mutex and the request_irq with request_threaded_irq.
A threaded IRQ is slower than a normal one but does allow mutexes.

	Arnd
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