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

[Lars-Peter Clausen <lars@metafoo.de>]

On 04/05/2013 04:56 PM, Doug Anderson wrote:
> Lars,
> 
> On Fri, Apr 5, 2013 at 1:53 AM, Lars-Peter Clausen <lars@metafoo.de> 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.

Yes, that could also work.

- Lars