RE: [PATCH v3] drm/i915/gen12: Disable preemption timeout

["Mrozek, Michal" <michal.mrozek@intel.com>]

> -----Original Message-----
> From: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Sent: Thursday, March 12, 2020 12:58 PM
> To: Intel-gfx@lists.freedesktop.org
> Cc: Ursulin, Tvrtko <tvrtko.ursulin@intel.com>; Chris Wilson <chris@chris-
> wilson.co.uk>; Joonas Lahtinen <joonas.lahtinen@linux.intel.com>; Mrozek,
> Michal <michal.mrozek@intel.com>; stable@vger.kernel.org
> Subject: [PATCH v3] drm/i915/gen12: Disable preemption timeout
> 
> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> 
> Allow super long OpenCL workloads which cannot be preempted within the
> default timeout to run out of the box.
> 
> v2:
>  * Make it stick out more and apply only to RCS. (Chris)
> 
> v3:
>  * Mention platform override in kconfig. (Joonas)
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Michal Mrozek <michal.mrozek@intel.com>
> Cc: <stable@vger.kernel.org> # v5.6+
> Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/Kconfig.profile      |  4 ++++
>  drivers/gpu/drm/i915/gt/intel_engine_cs.c | 13 +++++++++----
>  2 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/Kconfig.profile
> b/drivers/gpu/drm/i915/Kconfig.profile
> index ba8767fc0d6e..0bfd276c19fe 100644
> --- a/drivers/gpu/drm/i915/Kconfig.profile
> +++ b/drivers/gpu/drm/i915/Kconfig.profile
> @@ -41,6 +41,10 @@ config DRM_I915_PREEMPT_TIMEOUT
> 
>  	  May be 0 to disable the timeout.
> 
> +	  The compiled in default may get overridden at driver probe time on
> +	  certain platforms and certain engines which will be reflected in the
> +	  sysfs control.
> +
>  config DRM_I915_MAX_REQUEST_BUSYWAIT
>  	int "Busywait for request completion limit (ns)"
>  	default 8000 # nanoseconds
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> index 8eeec87b7d72..3aa8a652c16d 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> @@ -275,6 +275,7 @@ static void intel_engine_sanitize_mmio(struct
> intel_engine_cs *engine)  static int intel_engine_setup(struct intel_gt *gt, enum
> intel_engine_id id)  {
>  	const struct engine_info *info = &intel_engines[id];
> +	struct drm_i915_private *i915 = gt->i915;
>  	struct intel_engine_cs *engine;
> 
>  	BUILD_BUG_ON(MAX_ENGINE_CLASS >=
> BIT(GEN11_ENGINE_CLASS_WIDTH)); @@ -301,11 +302,11 @@ static int
> intel_engine_setup(struct intel_gt *gt, enum intel_engine_id id)
>  	engine->id = id;
>  	engine->legacy_idx = INVALID_ENGINE;
>  	engine->mask = BIT(id);
> -	engine->i915 = gt->i915;
> +	engine->i915 = i915;
>  	engine->gt = gt;
>  	engine->uncore = gt->uncore;
>  	engine->hw_id = engine->guc_id = info->hw_id;
> -	engine->mmio_base = __engine_mmio_base(gt->i915, info-
> >mmio_bases);
> +	engine->mmio_base = __engine_mmio_base(i915, info->mmio_bases);
> 
>  	engine->class = info->class;
>  	engine->instance = info->instance;
> @@ -322,11 +323,15 @@ static int intel_engine_setup(struct intel_gt *gt, enum
> intel_engine_id id)
>  	engine->props.timeslice_duration_ms =
>  		CONFIG_DRM_I915_TIMESLICE_DURATION;
> 
> +	/* Override to uninterruptible for OpenCL workloads. */
> +	if (INTEL_GEN(i915) == 12 && engine->class == RENDER_CLASS)
> +		engine->props.preempt_timeout_ms = 0;
> +
>  	engine->context_size = intel_engine_context_size(gt, engine->class);
>  	if (WARN_ON(engine->context_size > BIT(20)))
>  		engine->context_size = 0;
>  	if (engine->context_size)
> -		DRIVER_CAPS(gt->i915)->has_logical_contexts = true;
> +		DRIVER_CAPS(i915)->has_logical_contexts = true;
> 
>  	/* Nothing to do here, execute in order of dependencies */
>  	engine->schedule = NULL;
> @@ -342,7 +347,7 @@ static int intel_engine_setup(struct intel_gt *gt, enum
> intel_engine_id id)
>  	gt->engine_class[info->class][info->instance] = engine;
>  	gt->engine[id] = engine;
> 
> -	gt->i915->engine[id] = engine;
> +	i915->engine[id] = engine;
> 
>  	return 0;
>  }
> --
> 2.20.1

Acked-by: Michal Mrozek <Michal.mrozek@intel.com>