[PATCH] drm/i915/guc: Don't send policy update for child contexts.

[John Harrison]

On 7/27/2022 17:33, Daniele Ceraolo Spurio wrote:
> The GuC FW applies the parent context policy to all the children,
> so individual updates to the children are not supported and we
> should not send them.
>
> Note that sending the message did not have any functional consequences,
> because the GuC just drops it and logs an error; since we were trying
> to set the child policy to match the parent anyway the message being
> dropped was not a problem.
>
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: John Harrison <john.c.harrison at intel.com>
Needs a Fixes tag for the original v70 update patch?

John.

> ---
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 26 +------------------
>   1 file changed, 1 insertion(+), 25 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index 76916aed897a..5e31e2540297 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -2420,7 +2420,6 @@ static int guc_context_policy_init_v70(struct intel_context *ce, bool loop)
>   	struct context_policy policy;
>   	u32 execution_quantum;
>   	u32 preemption_timeout;
> -	bool missing = false;
>   	unsigned long flags;
>   	int ret;
>   
> @@ -2438,32 +2437,9 @@ static int guc_context_policy_init_v70(struct intel_context *ce, bool loop)
>   		__guc_context_policy_add_preempt_to_idle(&policy, 1);
>   
>   	ret = __guc_context_set_context_policies(guc, &policy, loop);
> -	missing = ret != 0;
> -
> -	if (!missing && intel_context_is_parent(ce)) {
> -		struct intel_context *child;
> -
> -		for_each_child(ce, child) {
> -			__guc_context_policy_start_klv(&policy, child->guc_id.id);
> -
> -			if (engine->flags & I915_ENGINE_WANT_FORCED_PREEMPTION)
> -				__guc_context_policy_add_preempt_to_idle(&policy, 1);
> -
> -			child->guc_state.prio = ce->guc_state.prio;
> -			__guc_context_policy_add_priority(&policy, ce->guc_state.prio);
> -			__guc_context_policy_add_execution_quantum(&policy, execution_quantum);
> -			__guc_context_policy_add_preemption_timeout(&policy, preemption_timeout);
> -
> -			ret = __guc_context_set_context_policies(guc, &policy, loop);
> -			if (ret) {
> -				missing = true;
> -				break;
> -			}
> -		}
> -	}
>   
>   	spin_lock_irqsave(&ce->guc_state.lock, flags);
> -	if (missing)
> +	if (ret != 0)
>   		set_context_policy_required(ce);
>   	else
>   		clr_context_policy_required(ce);