[Intel-gfx] [PATCH 6/8] drm/i915/guc: Keep the engine awake until the tasklet is idle

[Chris Wilson]

Quoting Chris Wilson (2019-08-12 10:10:43)
> For the guc, we need to keep the engine awake (and not parked) and not
> just the gt. If we let the engine park, we disable the irq and stop
> processing the tasklet, leaving state outstanding inside the tasklet.
> 
> The downside is, of course, we now have to wait until the tasklet is run
> before we consider the engine idle.

Fwiw, because of this I think it may be preferable to keep to using GT
pm for the tasklet; and apply Daniele's patch to keep
NEEDS_BREADCRUMB_TASKLET set (which is the right thing to do anyway now
that we stop switching between submission modes).
-Chris