drm/i915/selftests: Drop live_preempt_hang

live_preempt_hang's use of hang injection has been superseded by
live_preempt_reset's use of an non-preemptible spinner. The latter does
not require intrusive hacks into the code.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200209230838.361154-2-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_engine.h

@@ -305,26 +305,6 @@ intel_engine_find_active_request(struct intel_engine_cs *engine);
 
 u32 intel_engine_context_size(struct intel_gt *gt, u8 class);
 
-#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
-
-static inline bool inject_preempt_hang(struct intel_engine_execlists *execlists)
-{
-	if (!execlists->preempt_hang.inject_hang)
-		return false;
-
-	complete(&execlists->preempt_hang.completion);
-	return true;
-}
-
-#else
-
-static inline bool inject_preempt_hang(struct intel_engine_execlists *execlists)
-{
-	return false;
-}
-
-#endif
-
 void intel_engine_init_active(struct intel_engine_cs *engine,
 			      unsigned int subclass);
 #define ENGINE_PHYSICAL	0

drivers/gpu/drm/i915/gt/intel_engine_types.h

@@ -127,7 +127,6 @@ DECLARE_EWMA(_engine_latency, 6, 4)
 struct st_preempt_hang {
 	struct completion completion;
 	unsigned int count;
-	bool inject_hang;
 };
 
 /**

drivers/gpu/drm/i915/gt/intel_lrc.c

@@ -2296,19 +2296,19 @@ static void process_csb(struct intel_engine_cs *engine)
 		if (promote) {
 			struct i915_request * const *old = execlists->active;
 
-			/* Point active to the new ELSP; prevent overwriting */
-			WRITE_ONCE(execlists->active, execlists->pending);
+			GEM_BUG_ON(!assert_pending_valid(execlists, "promote"));
 
-			if (!inject_preempt_hang(execlists))
 			ring_set_paused(engine, 0);
 
+			/* Point active to the new ELSP; prevent overwriting */
+			WRITE_ONCE(execlists->active, execlists->pending);
+
 			/* cancel old inflight, prepare for switch */
 			trace_ports(execlists, "preempted", old);
 			while (*old)
 				execlists_schedule_out(*old++);
 
 			/* switch pending to inflight */
-			GEM_BUG_ON(!assert_pending_valid(execlists, "promote"));
 			WRITE_ONCE(execlists->active,
 				   memcpy(execlists->inflight,
 					  execlists->pending,

drivers/gpu/drm/i915/gt/selftest_lrc.c

@@ -2431,127 +2431,6 @@ static int live_preempt_gang(void *arg)
 	return 0;
 }
 
-static int live_preempt_hang(void *arg)
-{
-	struct intel_gt *gt = arg;
-	struct i915_gem_context *ctx_hi, *ctx_lo;
-	struct igt_spinner spin_hi, spin_lo;
-	struct intel_engine_cs *engine;
-	enum intel_engine_id id;
-	int err = -ENOMEM;
-
-	if (!HAS_LOGICAL_RING_PREEMPTION(gt->i915))
-		return 0;
-
-	if (!intel_has_reset_engine(gt))
-		return 0;
-
-	if (igt_spinner_init(&spin_hi, gt))
-		return -ENOMEM;
-
-	if (igt_spinner_init(&spin_lo, gt))
-		goto err_spin_hi;
-
-	ctx_hi = kernel_context(gt->i915);
-	if (!ctx_hi)
-		goto err_spin_lo;
-	ctx_hi->sched.priority =
-		I915_USER_PRIORITY(I915_CONTEXT_MAX_USER_PRIORITY);
-
-	ctx_lo = kernel_context(gt->i915);
-	if (!ctx_lo)
-		goto err_ctx_hi;
-	ctx_lo->sched.priority =
-		I915_USER_PRIORITY(I915_CONTEXT_MIN_USER_PRIORITY);
-
-	for_each_engine(engine, gt, id) {
-		unsigned long heartbeat;
-		struct i915_request *rq;
-
-		if (!intel_engine_has_preemption(engine))
-			continue;
-
-		engine_heartbeat_disable(engine, &heartbeat);
-
-		rq = spinner_create_request(&spin_lo, ctx_lo, engine,
-					    MI_ARB_CHECK);
-		if (IS_ERR(rq)) {
-			err = PTR_ERR(rq);
-			engine_heartbeat_enable(engine, heartbeat);
-			goto err_ctx_lo;
-		}
-
-		i915_request_add(rq);
-		if (!igt_wait_for_spinner(&spin_lo, rq)) {
-			GEM_TRACE("lo spinner failed to start\n");
-			GEM_TRACE_DUMP();
-			intel_gt_set_wedged(gt);
-			err = -EIO;
-			engine_heartbeat_enable(engine, heartbeat);
-			goto err_ctx_lo;
-		}
-
-		rq = spinner_create_request(&spin_hi, ctx_hi, engine,
-					    MI_ARB_CHECK);
-		if (IS_ERR(rq)) {
-			igt_spinner_end(&spin_lo);
-			engine_heartbeat_enable(engine, heartbeat);
-			err = PTR_ERR(rq);
-			goto err_ctx_lo;
-		}
-
-		init_completion(&engine->execlists.preempt_hang.completion);
-		engine->execlists.preempt_hang.inject_hang = true;
-
-		i915_request_add(rq);
-
-		if (!wait_for_completion_timeout(&engine->execlists.preempt_hang.completion,
-						 HZ / 10)) {
-			pr_err("Preemption did not occur within timeout!");
-			GEM_TRACE_DUMP();
-			intel_gt_set_wedged(gt);
-			engine_heartbeat_enable(engine, heartbeat);
-			err = -EIO;
-			goto err_ctx_lo;
-		}
-
-		set_bit(I915_RESET_ENGINE + id, &gt->reset.flags);
-		intel_engine_reset(engine, NULL);
-		clear_bit(I915_RESET_ENGINE + id, &gt->reset.flags);
-
-		engine->execlists.preempt_hang.inject_hang = false;
-
-		if (!igt_wait_for_spinner(&spin_hi, rq)) {
-			GEM_TRACE("hi spinner failed to start\n");
-			GEM_TRACE_DUMP();
-			intel_gt_set_wedged(gt);
-			engine_heartbeat_enable(engine, heartbeat);
-			err = -EIO;
-			goto err_ctx_lo;
-		}
-
-		igt_spinner_end(&spin_hi);
-		igt_spinner_end(&spin_lo);
-		engine_heartbeat_enable(engine, heartbeat);
-
-		if (igt_flush_test(gt->i915)) {
-			err = -EIO;
-			goto err_ctx_lo;
-		}
-	}
-
-	err = 0;
-err_ctx_lo:
-	kernel_context_close(ctx_lo);
-err_ctx_hi:
-	kernel_context_close(ctx_hi);
-err_spin_lo:
-	igt_spinner_fini(&spin_lo);
-err_spin_hi:
-	igt_spinner_fini(&spin_hi);
-	return err;
-}
-
 static int live_preempt_timeout(void *arg)
 {
 	struct intel_gt *gt = arg;
@@ -3750,7 +3629,6 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915)
 		SUBTEST(live_suppress_wait_preempt),
 		SUBTEST(live_chain_preempt),
 		SUBTEST(live_preempt_gang),
-		SUBTEST(live_preempt_hang),
 		SUBTEST(live_preempt_timeout),
 		SUBTEST(live_preempt_smoke),
 		SUBTEST(live_virtual_engine),