Commit 7d6ce558 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Remove has-kernel-context 



We can no longer assume execution ordering, and in particular we cannot
assume which context will execute last. One side-effect of this is that
we cannot determine if the kernel-context is resident on the GPU, so
remove the routines that claimed to do so.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190308093657.8640-4-chris@chris-wilson.co.uk
parent c6eeb479

drivers/gpu/drm/i915/i915_active.h

+0 −13
Original line number Diff line number Diff line
@@ -108,19 +108,6 @@ i915_active_request_set_retire_fn(struct i915_active_request *active, 
	active->retire = fn ?: i915_active_retire_noop;

}



static inline struct i915_request *

__i915_active_request_peek(const struct i915_active_request *active)

{

	/*

	 * Inside the error capture (running with the driver in an unknown

	 * state), we want to bend the rules slightly (a lot).

	 *

	 * Work is in progress to make it safer, in the meantime this keeps

	 * the known issue from spamming the logs.

	 */

	return rcu_dereference_protected(active->request, 1);

}



/**

 * i915_active_request_raw - return the active request

 * @active - the active tracker

drivers/gpu/drm/i915/i915_gem.c

+1 −20
Original line number Diff line number Diff line
@@ -2828,23 +2828,6 @@ i915_gem_retire_work_handler(struct work_struct *work) 
				   round_jiffies_up_relative(HZ));

}



static void assert_kernel_context_is_current(struct drm_i915_private *i915)

{

	struct intel_engine_cs *engine;

	enum intel_engine_id id;



	if (i915_reset_failed(i915))

		return;



	i915_retire_requests(i915);



	for_each_engine(engine, i915, id) {

		GEM_BUG_ON(__i915_active_request_peek(&engine->timeline.last_request));

		GEM_BUG_ON(engine->last_retired_context !=

			   to_intel_context(i915->kernel_context, engine));

	}

}



static bool switch_to_kernel_context_sync(struct drm_i915_private *i915,

					  unsigned long mask)

{
@@ -2864,9 +2847,7 @@ static bool switch_to_kernel_context_sync(struct drm_i915_private *i915, 
				   I915_GEM_IDLE_TIMEOUT))

		result = false;



	if (result) {

		assert_kernel_context_is_current(i915);

	} else {

	if (!result) {

		/* Forcibly cancel outstanding work and leave the gpu quiet. */

		dev_err(i915->drm.dev,

			"Failed to idle engines, declaring wedged!\n");

drivers/gpu/drm/i915/i915_gem_evict.c

+3 −13
Original line number Diff line number Diff line
@@ -38,25 +38,15 @@ I915_SELFTEST_DECLARE(static struct igt_evict_ctl { 


static bool ggtt_is_idle(struct drm_i915_private *i915)

{

       struct intel_engine_cs *engine;

       enum intel_engine_id id;



       if (i915->gt.active_requests)

	       return false;



       for_each_engine(engine, i915, id) {

	       if (!intel_engine_has_kernel_context(engine))

		       return false;

       }



       return true;

	return !i915->gt.active_requests;

}



static int ggtt_flush(struct drm_i915_private *i915)

{

	int err;



	/* Not everything in the GGTT is tracked via vma (otherwise we

	/*

	 * Not everything in the GGTT is tracked via vma (otherwise we

	 * could evict as required with minimal stalling) so we are forced

	 * to idle the GPU and explicitly retire outstanding requests in

	 * the hopes that we can then remove contexts and the like only

drivers/gpu/drm/i915/intel_engine_cs.c

+0 −31
Original line number Diff line number Diff line
@@ -1090,37 +1090,6 @@ bool intel_engines_are_idle(struct drm_i915_private *i915) 
	return true;

}



/**

 * intel_engine_has_kernel_context:

 * @engine: the engine

 *

 * Returns true if the last context to be executed on this engine, or has been

 * executed if the engine is already idle, is the kernel context

 * (#i915.kernel_context).

 */

bool intel_engine_has_kernel_context(const struct intel_engine_cs *engine)

{

	const struct intel_context *kernel_context =

		to_intel_context(engine->i915->kernel_context, engine);

	struct i915_request *rq;



	lockdep_assert_held(&engine->i915->drm.struct_mutex);



	if (!engine->context_size)

		return true;



	/*

	 * Check the last context seen by the engine. If active, it will be

	 * the last request that remains in the timeline. When idle, it is

	 * the last executed context as tracked by retirement.

	 */

	rq = __i915_active_request_peek(&engine->timeline.last_request);

	if (rq)

		return rq->hw_context == kernel_context;

	else

		return engine->last_retired_context == kernel_context;

}



void intel_engines_reset_default_submission(struct drm_i915_private *i915)

{

	struct intel_engine_cs *engine;

drivers/gpu/drm/i915/intel_ringbuffer.h

+0 −1
Original line number Diff line number Diff line
@@ -935,7 +935,6 @@ void intel_engines_sanitize(struct drm_i915_private *i915, bool force); 
bool intel_engine_is_idle(struct intel_engine_cs *engine);

bool intel_engines_are_idle(struct drm_i915_private *dev_priv);



bool intel_engine_has_kernel_context(const struct intel_engine_cs *engine);

void intel_engine_lost_context(struct intel_engine_cs *engine);



void intel_engines_park(struct drm_i915_private *i915);

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