Re: [PATCH 1/7] drm/i915: Remove tasklet flush before disable

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

Chris Wilson <chris@chris-wilson.co.uk> writes:

> Quoting Mika Kuoppala (2018-05-16 09:39:14)
>> Chris Wilson <chris@chris-wilson.co.uk> writes:
>> 
>> > The idea was to try and let the existing tasklet run to completion
>> > before we began the reset, but it involves a racy check against anything
>> > else that tries to run the tasklet. Rather than acknowledge and ignore
>> > the race, let it be and don't try and be too clever.
>> >
>> > The tasklet will resume execution after reset (after spinning a bit
>> > during reset), but before we allow it to resume we will have cleared all
>> > the pending state.
>> 
>> The disable works only on all future reschedules and
>> the dequeue is behind timeline lock. But what guards against
>> the tasklet being currently reading the ports?
>
> tasklet_disable() itself is synchronous and waits for completion of the
> current execution before returning. See tasklet_disable_nosync() for the
> complimentary function just to prevent future schedules from executing.

Ok, so the spinning is on the tasklet infra when it spins on
scheduling, not being able to call the tasklet->func().

Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>

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