[Intel-gfx] [PATCH] drm/i915: Tracking waiters for execution wrt hangcheck

[Chris Wilson]

Quoting Chris Wilson (2018-01-29 13:50:13)
> Hangcheck wants to turn itself off when no one is listening (to save
> needless wakeups). However, we now may have waiters that are not waiting
> for requests already on the GPU, but waiting for requests deep in the
> queue for execution, and do not have an irq alloted. Therefore, inside
> hangcheck we can not simply just check if any waiter has an irq
> assigned, but can look at whether anyone is listening for hangcheck
> signals.

This is not sufficient for unlocked waits. (Although I might argue
that all waits eventually hit somebody who will wait.) I am thinking
that we move hangcheck over to mark_busy.
-Chris