Re: [RFC: PATCH 2/2] iio: adc: exynos_adc: Handle timeout and race conditions

[Doug Anderson]

Lars,

On Fri, Apr 5, 2013 at 1:53 AM, Lars-Peter Clausen <lars@xxxxxxxxxx> wrote:
> Since we sleep inside the protected section we need to use a mutex.

Ah, good point.

> It's not the timeout case I'm worried about, but the case where the transfer
> is interrupted by the user. Even though it is rather unlikely for the
> problem to occur we should still try to avoid it, this is one of these
> annoying heisenbugs that happen once in a while and nobody is able to
> reproduce them.

Yes, of course.  Then we can also get extra confidence that the reset
logic works well by stressing out this case...  :)

This makes me think, though.  Given how fast we expect the ADC
transaction to finish, would there be any benefit to making the wait
non-interruptible and then shortening the timeout a whole lot.  If we
shortened to 1ms then we're really not "non-interruptible" for very
long and there's less chance of subtle bugs in the way that reset
works.

-Doug
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