[Intel-gfx] [PATCH] drm/i915/gt: Disable preparser around MI_SEMAPHORE_WAIT

[Chris Wilson]

Quoting Chris Wilson (2020-12-08 18:57:02)
> @@ -5015,6 +5010,7 @@ gen11_emit_fini_breadcrumb_rcs(struct i915_request *request, u32 *cs)
>  
>  static u32 *gen12_emit_preempt_busywait(struct i915_request *request, u32 *cs)
>  {
> +       *cs++ = gen12_preparser_disable(true); /* Wa_1607297627:tgl,dg1,rkl */
>         *cs++ = MI_SEMAPHORE_WAIT_TOKEN |
>                 MI_SEMAPHORE_GLOBAL_GTT |
>                 MI_SEMAPHORE_POLL |

I'm wondering if MI_SEMAPHORE_POLL prevents idling & RDOP, so the w/a is
not required?
-Chris