Re: [PATCH 18/47] drm/i915: Disable preempt busywait when using GuC scheduling

[John Harrison <john.c.harrison@xxxxxxxxx>]

On 6/24/2021 00:04, Matthew Brost wrote:
> Disable preempt busywait when using GuC scheduling. This isn't need as
needed

> the GuC control preemption when scheduling.
controls

With the above fixed:
Reviewed-by: John Harrison <John.C.Harrison@xxxxxxxxx>


> Cc: John Harrison <john.c.harrison@xxxxxxxxx>
> Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> ---
>   drivers/gpu/drm/i915/gt/gen8_engine_cs.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/gen8_engine_cs.c b/drivers/gpu/drm/i915/gt/gen8_engine_cs.c
> index 87b06572fd2e..f7aae502ec3d 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_engine_cs.c
> +++ b/drivers/gpu/drm/i915/gt/gen8_engine_cs.c
> @@ -506,7 +506,8 @@ gen8_emit_fini_breadcrumb_tail(struct i915_request *rq, u32 *cs)
>   	*cs++ = MI_USER_INTERRUPT;
>   
>   	*cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
> -	if (intel_engine_has_semaphores(rq->engine))
> +	if (intel_engine_has_semaphores(rq->engine) &&
> +	    !intel_uc_uses_guc_submission(&rq->engine->gt->uc))
>   		cs = emit_preempt_busywait(rq, cs);
>   
>   	rq->tail = intel_ring_offset(rq, cs);
> @@ -598,7 +599,8 @@ gen12_emit_fini_breadcrumb_tail(struct i915_request *rq, u32 *cs)
>   	*cs++ = MI_USER_INTERRUPT;
>   
>   	*cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
> -	if (intel_engine_has_semaphores(rq->engine))
> +	if (intel_engine_has_semaphores(rq->engine) &&
> +	    !intel_uc_uses_guc_submission(&rq->engine->gt->uc))
>   		cs = gen12_emit_preempt_busywait(rq, cs);
>   
>   	rq->tail = intel_ring_offset(rq, cs);