[Intel-gfx] [PATCH] drm/i915: Introduce i915_gem_fini_hw for symmetry with i915_gem_init_hw

[Chris Wilson]

Quoting Michal Wajdeczko (2018-10-12 14:26:09)
> In function i915_gem_init_hw we are initializing some uC code that

i915_gem_init_hw really shouldn't be called such, at least it doesn't
fit in with the global init_hw phase. Suggestions for a clearer name
welcome.

> requires some cleanup. Then during unwind we call this uC cleanup
> function directly which breaks symmetry and layering. Fix that by
> adding i915_gem_fini_hw for symmetry with i915_gem_init_hw.

There's a lot that we do in init_hw that we presume will be undone by
reset. The asymmetry looks inherent, but I wonder if it would be better
expressed as we are missing a global reset along the error path.

It also has to be said that we cannot support intel_uc_init_hw() from
within a struct_mutex-less i915_reset. (I have a patch to disable global
reset while guc is enabled to avoid the deadlock, forcing us to rely on
per-engine resets in that case).

Anyway, I'm hesitant to call the suggested i915_gem_fini_hw() as the
compliment to i915_gem_init_hw() and feel a little more convincing is in
order.
-Chris