drivers/gpu/drm/i915/gt/selftest_engine_pm.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright © 2018 Intel Corporation
  */

 #include <linux/sort.h>

 #include "gt/intel_gt_print.h"
 #include "i915_selftest.h"
 #include "intel_engine_regs.h"
 #include "intel_gpu_commands.h"
 #include "intel_gt_clock_utils.h"
 #include "selftest_engine.h"
 #include "selftest_engine_heartbeat.h"
 #include "selftests/igt_atomic.h"
 #include "selftests/igt_flush_test.h"
 #include "selftests/igt_spinner.h"

 #define COUNT 5

 static int cmp_u64(const void *A, const void *B)
 {
 	const u64 *a = A, *b = B;

 	return *a - *b;
 }

 static u64 trifilter(u64 *a)
 {
 	sort(a, COUNT, sizeof(*a), cmp_u64, NULL);
 	return (a[1] + 2 * a[2] + a[3]) >> 2;
 }

 static u32 *emit_wait(u32 *cs, u32 offset, int op, u32 value)
 {
 	*cs++ = MI_SEMAPHORE_WAIT |
 		MI_SEMAPHORE_GLOBAL_GTT |
 		MI_SEMAPHORE_POLL |
 		op;
 	*cs++ = value;
 	*cs++ = offset;
 	*cs++ = 0;

 	return cs;
 }

 static u32 *emit_store(u32 *cs, u32 offset, u32 value)
 {
 	*cs++ = MI_STORE_DWORD_IMM_GEN4 | MI_USE_GGTT;
 	*cs++ = offset;
 	*cs++ = 0;
 	*cs++ = value;

 	return cs;
 }

 static u32 *emit_srm(u32 *cs, i915_reg_t reg, u32 offset)
 {
 	*cs++ = MI_STORE_REGISTER_MEM_GEN8 | MI_USE_GGTT;
 	*cs++ = i915_mmio_reg_offset(reg);
 	*cs++ = offset;
 	*cs++ = 0;

 	return cs;
 }

 static void write_semaphore(u32 *x, u32 value)
 {
 	WRITE_ONCE(*x, value);
 	wmb();
 }

 static int __measure_timestamps(struct intel_context *ce,
 				u64 *dt, u64 *d_ring, u64 *d_ctx)
 {
 	struct intel_engine_cs *engine = ce->engine;
 	u32 *sema = memset32(engine->status_page.addr + 1000, 0, 5);
 	u32 offset = i915_ggtt_offset(engine->status_page.vma);
 	struct i915_request *rq;
 	u32 *cs;

 	rq = intel_context_create_request(ce);
 	if (IS_ERR(rq))
 		return PTR_ERR(rq);

 	cs = intel_ring_begin(rq, 28);
 	if (IS_ERR(cs)) {
 		i915_request_add(rq);
 		return PTR_ERR(cs);
 	}

 	/* Signal & wait for start */
 	cs = emit_store(cs, offset + 4008, 1);
 	cs = emit_wait(cs, offset + 4008, MI_SEMAPHORE_SAD_NEQ_SDD, 1);

 	cs = emit_srm(cs, RING_TIMESTAMP(engine->mmio_base), offset + 4000);
 	cs = emit_srm(cs, RING_CTX_TIMESTAMP(engine->mmio_base), offset + 4004);

 	/* Busy wait */
 	cs = emit_wait(cs, offset + 4008, MI_SEMAPHORE_SAD_EQ_SDD, 1);

 	cs = emit_srm(cs, RING_TIMESTAMP(engine->mmio_base), offset + 4016);
 	cs = emit_srm(cs, RING_CTX_TIMESTAMP(engine->mmio_base), offset + 4012);

 	intel_ring_advance(rq, cs);
 	i915_request_get(rq);
 	i915_request_add(rq);
 	intel_engine_flush_submission(engine);

 	/* Wait for the request to start executing, that then waits for us */
 	while (READ_ONCE(sema[2]) == 0)
 		cpu_relax();

 	/* Run the request for a 100us, sampling timestamps before/after */
 	local_irq_disable();
 	write_semaphore(&sema[2], 0);
 	while (READ_ONCE(sema[1]) == 0) /* wait for the gpu to catch up */
 		cpu_relax();
 	*dt = local_clock();
 	udelay(100);
 	*dt = local_clock() - *dt;
 	write_semaphore(&sema[2], 1);
 	local_irq_enable();

 	if (i915_request_wait(rq, 0, HZ / 2) < 0) {
 		i915_request_put(rq);
 		return -ETIME;
 	}
 	i915_request_put(rq);

 	pr_debug("%s CTX_TIMESTAMP: [%x, %x], RING_TIMESTAMP: [%x, %x]\n",
 		 engine->name, sema[1], sema[3], sema[0], sema[4]);

 	*d_ctx = sema[3] - sema[1];
 	*d_ring = sema[4] - sema[0];
 	return 0;
 }

 static int __live_engine_timestamps(struct intel_engine_cs *engine)
 {
 	u64 s_ring[COUNT], s_ctx[COUNT], st[COUNT], d_ring, d_ctx, dt;
 	struct intel_context *ce;
 	int i, err = 0;

 	ce = intel_context_create(engine);
 	if (IS_ERR(ce))
 		return PTR_ERR(ce);

 	for (i = 0; i < COUNT; i++) {
 		err = __measure_timestamps(ce, &st[i], &s_ring[i], &s_ctx[i]);
 		if (err)
 			break;
 	}
 	intel_context_put(ce);
 	if (err)
 		return err;

 	dt = trifilter(st);
 	d_ring = trifilter(s_ring);
 	d_ctx = trifilter(s_ctx);

 	pr_info("%s elapsed:%lldns, CTX_TIMESTAMP:%lldns, RING_TIMESTAMP:%lldns\n",
 		engine->name, dt,
 		intel_gt_clock_interval_to_ns(engine->gt, d_ctx),
 		intel_gt_clock_interval_to_ns(engine->gt, d_ring));

 	d_ring = intel_gt_clock_interval_to_ns(engine->gt, d_ring);
 	if (3 * dt > 4 * d_ring || 4 * dt < 3 * d_ring) {
 		pr_err("%s Mismatch between ring timestamp and walltime!\n",
 		       engine->name);
 		return -EINVAL;
 	}

 	d_ring = trifilter(s_ring);
 	d_ctx = trifilter(s_ctx);

 	d_ctx *= engine->gt->clock_frequency;
 	if (GRAPHICS_VER(engine->i915) == 11)
 		d_ring *= 12500000; /* Fixed 80ns for GEN11 ctx timestamp? */
 	else
 		d_ring *= engine->gt->clock_frequency;

 	if (3 * d_ctx > 4 * d_ring || 4 * d_ctx < 3 * d_ring) {
 		pr_err("%s Mismatch between ring and context timestamps!\n",
 		       engine->name);
 		return -EINVAL;
 	}

 	return 0;
 }

 static int live_engine_timestamps(void *arg)
 {
 	struct intel_gt *gt = arg;
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;

 	/*
 	 * Check that CS_TIMESTAMP / CTX_TIMESTAMP are in sync, i.e. share
 	 * the same CS clock.
 	 */

 	if (GRAPHICS_VER(gt->i915) < 8)
 		return 0;

 	for_each_engine(engine, gt, id) {
 		int err;

 		st_engine_heartbeat_disable(engine);
 		err = __live_engine_timestamps(engine);
 		st_engine_heartbeat_enable(engine);
 		if (err)
 			return err;
 	}

 	return 0;
 }

 static int __spin_until_busier(struct intel_engine_cs *engine, ktime_t busyness)
 {
 	ktime_t start, unused, dt;

 	if (!intel_engine_uses_guc(engine))
 		return 0;

 	/*
 	 * In GuC mode of submission, the busyness stats may get updated after
 	 * the batch starts running. Poll for a change in busyness and timeout
 	 * after 500 us.
 	 */
 	start = ktime_get();
 	while (intel_engine_get_busy_time(engine, &unused) == busyness) {
 		dt = ktime_get() - start;
 		if (dt > 10000000) {
 			pr_err("active wait timed out %lld\n", dt);
 			ENGINE_TRACE(engine, "active wait time out %lld\n", dt);
 			return -ETIME;
 		}
 	}

 	return 0;
 }

 static int live_engine_busy_stats(void *arg)
 {
 	struct intel_gt *gt = arg;
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
 	struct igt_spinner spin;
 	int err = 0;

 	/*
 	 * Check that if an engine supports busy-stats, they tell the truth.
 	 */

 	if (igt_spinner_init(&spin, gt))
 		return -ENOMEM;

 	GEM_BUG_ON(intel_gt_pm_is_awake(gt));
 	for_each_engine(engine, gt, id) {
 		struct i915_request *rq;
 		ktime_t busyness, dummy;
 		ktime_t de, dt;
 		ktime_t t[2];

 		if (!intel_engine_supports_stats(engine))
 			continue;

 		if (!intel_engine_can_store_dword(engine))
 			continue;

 		if (intel_gt_pm_wait_for_idle(gt)) {
 			err = -EBUSY;
 			break;
 		}

 		st_engine_heartbeat_disable(engine);

 		ENGINE_TRACE(engine, "measuring idle time\n");
 		preempt_disable();
 		de = intel_engine_get_busy_time(engine, &t[0]);
 		udelay(100);
 		de = ktime_sub(intel_engine_get_busy_time(engine, &t[1]), de);
 		preempt_enable();
 		dt = ktime_sub(t[1], t[0]);
 		if (de < 0 || de > 10) {
 			pr_err("%s: reported %lldns [%d%%] busyness while sleeping [for %lldns]\n",
 			       engine->name,
 			       de, (int)div64_u64(100 * de, dt), dt);
 			GEM_TRACE_DUMP();
 			err = -EINVAL;
 			goto end;
 		}

 		/* 100% busy */
 		rq = igt_spinner_create_request(&spin,
 						engine->kernel_context,
 						MI_NOOP);
 		if (IS_ERR(rq)) {
 			err = PTR_ERR(rq);
 			goto end;
 		}
 		i915_request_add(rq);

 		busyness = intel_engine_get_busy_time(engine, &dummy);
 		if (!igt_wait_for_spinner(&spin, rq)) {
 			intel_gt_set_wedged(engine->gt);
 			err = -ETIME;
 			goto end;
 		}

 		err = __spin_until_busier(engine, busyness);
 		if (err) {
 			GEM_TRACE_DUMP();
 			goto end;
 		}

 		ENGINE_TRACE(engine, "measuring busy time\n");
 		preempt_disable();
 		de = intel_engine_get_busy_time(engine, &t[0]);
 		mdelay(100);
 		de = ktime_sub(intel_engine_get_busy_time(engine, &t[1]), de);
 		preempt_enable();
 		dt = ktime_sub(t[1], t[0]);
 		if (100 * de < 95 * dt || 95 * de > 100 * dt) {
 			pr_err("%s: reported %lldns [%d%%] busyness while spinning [for %lldns]\n",
 			       engine->name,
 			       de, (int)div64_u64(100 * de, dt), dt);
 			GEM_TRACE_DUMP();
 			err = -EINVAL;
 			goto end;
 		}

 end:
 		st_engine_heartbeat_enable(engine);
 		igt_spinner_end(&spin);
 		if (igt_flush_test(gt->i915))
 			err = -EIO;
 		if (err)
 			break;
 	}

 	igt_spinner_fini(&spin);
 	if (igt_flush_test(gt->i915))
 		err = -EIO;
 	return err;
 }

 static int live_engine_pm(void *arg)
 {
 	struct intel_gt *gt = arg;
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;

 	/*
 	 * Check we can call intel_engine_pm_put from any context. No
 	 * failures are reported directly, but if we mess up lockdep should
 	 * tell us.
 	 */
 	if (intel_gt_pm_wait_for_idle(gt)) {
 		pr_err("Unable to flush GT pm before test\n");
 		return -EBUSY;
 	}

 	GEM_BUG_ON(intel_gt_pm_is_awake(gt));
 	for_each_engine(engine, gt, id) {
 		const typeof(*igt_atomic_phases) *p;

 		for (p = igt_atomic_phases; p->name; p++) {
 			/*
 			 * Acquisition is always synchronous, except if we
 			 * know that the engine is already awake, in which
 			 * case we should use intel_engine_pm_get_if_awake()
 			 * to atomically grab the wakeref.
 			 *
 			 * In practice,
 			 *    intel_engine_pm_get();
 			 *    intel_engine_pm_put();
 			 * occurs in one thread, while simultaneously
 			 *    intel_engine_pm_get_if_awake();
 			 *    intel_engine_pm_put();
 			 * occurs from atomic context in another.
 			 */
 			GEM_BUG_ON(intel_engine_pm_is_awake(engine));
 			intel_engine_pm_get(engine);

 			p->critical_section_begin();
 			if (!intel_engine_pm_get_if_awake(engine))
 				pr_err("intel_engine_pm_get_if_awake(%s) failed under %s\n",
 				       engine->name, p->name);
 			else
 				intel_engine_pm_put_async(engine);
 			intel_engine_pm_put_async(engine);
 			p->critical_section_end();

 			intel_engine_pm_flush(engine);

 			if (intel_engine_pm_is_awake(engine)) {
 				pr_err("%s is still awake after flushing pm\n",
 				       engine->name);
 				return -EINVAL;
 			}

 			/* gt wakeref is async (deferred to workqueue) */
 			if (intel_gt_pm_wait_for_idle(gt)) {
 				gt_err(gt, "GT failed to idle\n");
 				return -EINVAL;
 			}
 		}
 	}

 	return 0;
 }

 int live_engine_pm_selftests(struct intel_gt *gt)
 {
 	static const struct i915_subtest tests[] = {
 		SUBTEST(live_engine_timestamps),
 		SUBTEST(live_engine_busy_stats),
 		SUBTEST(live_engine_pm),
 	};

 	return intel_gt_live_subtests(tests, gt);
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright © 2018 Intel Corporation
	*/

	#include <linux/sort.h>

	#include "gt/intel_gt_print.h"
	#include "i915_selftest.h"
	#include "intel_engine_regs.h"
	#include "intel_gpu_commands.h"
	#include "intel_gt_clock_utils.h"
	#include "selftest_engine.h"
	#include "selftest_engine_heartbeat.h"
	#include "selftests/igt_atomic.h"
	#include "selftests/igt_flush_test.h"
	#include "selftests/igt_spinner.h"

	#define COUNT 5

	static int cmp_u64(const void A, const void B)
	{
	const u64 a = A, b = B;

	return a - b;
	}

	static u64 trifilter(u64 *a)
	{
	sort(a, COUNT, sizeof(*a), cmp_u64, NULL);
	return (a[1] + 2 * a[2] + a[3]) >> 2;
	}

	static u32 emit_wait(u32 cs, u32 offset, int op, u32 value)
	{
	*cs++ = MI_SEMAPHORE_WAIT \|
	MI_SEMAPHORE_GLOBAL_GTT \|
	MI_SEMAPHORE_POLL \|
	op;
	*cs++ = value;
	*cs++ = offset;
	*cs++ = 0;

	return cs;
	}

	static u32 emit_store(u32 cs, u32 offset, u32 value)
	{
	*cs++ = MI_STORE_DWORD_IMM_GEN4 \| MI_USE_GGTT;
	*cs++ = offset;
	*cs++ = 0;
	*cs++ = value;

	return cs;
	}

	static u32 emit_srm(u32 cs, i915_reg_t reg, u32 offset)
	{
	*cs++ = MI_STORE_REGISTER_MEM_GEN8 \| MI_USE_GGTT;
	*cs++ = i915_mmio_reg_offset(reg);
	*cs++ = offset;
	*cs++ = 0;

	return cs;
	}

	static void write_semaphore(u32 *x, u32 value)
	{
	WRITE_ONCE(*x, value);
	wmb();
	}

	static int __measure_timestamps(struct intel_context *ce,
	u64 dt, u64 d_ring, u64 *d_ctx)
	{
	struct intel_engine_cs *engine = ce->engine;
	u32 *sema = memset32(engine->status_page.addr + 1000, 0, 5);
	u32 offset = i915_ggtt_offset(engine->status_page.vma);
	struct i915_request *rq;
	u32 *cs;

	rq = intel_context_create_request(ce);
	if (IS_ERR(rq))
	return PTR_ERR(rq);

	cs = intel_ring_begin(rq, 28);
	if (IS_ERR(cs)) {
	i915_request_add(rq);
	return PTR_ERR(cs);
	}

	/* Signal & wait for start */
	cs = emit_store(cs, offset + 4008, 1);
	cs = emit_wait(cs, offset + 4008, MI_SEMAPHORE_SAD_NEQ_SDD, 1);

	cs = emit_srm(cs, RING_TIMESTAMP(engine->mmio_base), offset + 4000);
	cs = emit_srm(cs, RING_CTX_TIMESTAMP(engine->mmio_base), offset + 4004);

	/* Busy wait */
	cs = emit_wait(cs, offset + 4008, MI_SEMAPHORE_SAD_EQ_SDD, 1);

	cs = emit_srm(cs, RING_TIMESTAMP(engine->mmio_base), offset + 4016);
	cs = emit_srm(cs, RING_CTX_TIMESTAMP(engine->mmio_base), offset + 4012);

	intel_ring_advance(rq, cs);
	i915_request_get(rq);
	i915_request_add(rq);
	intel_engine_flush_submission(engine);

	/* Wait for the request to start executing, that then waits for us */
	while (READ_ONCE(sema[2]) == 0)
	cpu_relax();

	/* Run the request for a 100us, sampling timestamps before/after */
	local_irq_disable();
	write_semaphore(&sema[2], 0);
	while (READ_ONCE(sema[1]) == 0) /* wait for the gpu to catch up */
	cpu_relax();
	*dt = local_clock();
	udelay(100);
	dt = local_clock() - dt;
	write_semaphore(&sema[2], 1);
	local_irq_enable();

	if (i915_request_wait(rq, 0, HZ / 2) < 0) {
	i915_request_put(rq);
	return -ETIME;
	}
	i915_request_put(rq);

	pr_debug("%s CTX_TIMESTAMP: [%x, %x], RING_TIMESTAMP: [%x, %x]\n",
	engine->name, sema[1], sema[3], sema[0], sema[4]);

	*d_ctx = sema[3] - sema[1];
	*d_ring = sema[4] - sema[0];
	return 0;
	}

	static int __live_engine_timestamps(struct intel_engine_cs *engine)
	{
	u64 s_ring[COUNT], s_ctx[COUNT], st[COUNT], d_ring, d_ctx, dt;
	struct intel_context *ce;
	int i, err = 0;

	ce = intel_context_create(engine);
	if (IS_ERR(ce))
	return PTR_ERR(ce);

	for (i = 0; i < COUNT; i++) {
	err = __measure_timestamps(ce, &st[i], &s_ring[i], &s_ctx[i]);
	if (err)
	break;
	}
	intel_context_put(ce);
	if (err)
	return err;

	dt = trifilter(st);
	d_ring = trifilter(s_ring);
	d_ctx = trifilter(s_ctx);

	pr_info("%s elapsed:%lldns, CTX_TIMESTAMP:%lldns, RING_TIMESTAMP:%lldns\n",
	engine->name, dt,
	intel_gt_clock_interval_to_ns(engine->gt, d_ctx),
	intel_gt_clock_interval_to_ns(engine->gt, d_ring));

	d_ring = intel_gt_clock_interval_to_ns(engine->gt, d_ring);
	if (3 * dt > 4 * d_ring \|\| 4 * dt < 3 * d_ring) {
	pr_err("%s Mismatch between ring timestamp and walltime!\n",
	engine->name);
	return -EINVAL;
	}

	d_ring = trifilter(s_ring);
	d_ctx = trifilter(s_ctx);

	d_ctx *= engine->gt->clock_frequency;
	if (GRAPHICS_VER(engine->i915) == 11)
	d_ring = 12500000; / Fixed 80ns for GEN11 ctx timestamp? */
	else
	d_ring *= engine->gt->clock_frequency;

	if (3 * d_ctx > 4 * d_ring \|\| 4 * d_ctx < 3 * d_ring) {
	pr_err("%s Mismatch between ring and context timestamps!\n",
	engine->name);
	return -EINVAL;
	}

	return 0;
	}

	static int live_engine_timestamps(void *arg)
	{
	struct intel_gt *gt = arg;
	struct intel_engine_cs *engine;
	enum intel_engine_id id;

	/*
	* Check that CS_TIMESTAMP / CTX_TIMESTAMP are in sync, i.e. share
	* the same CS clock.
	*/

	if (GRAPHICS_VER(gt->i915) < 8)
	return 0;

	for_each_engine(engine, gt, id) {
	int err;

	st_engine_heartbeat_disable(engine);
	err = __live_engine_timestamps(engine);
	st_engine_heartbeat_enable(engine);
	if (err)
	return err;
	}

	return 0;
	}

	static int __spin_until_busier(struct intel_engine_cs *engine, ktime_t busyness)
	{
	ktime_t start, unused, dt;

	if (!intel_engine_uses_guc(engine))
	return 0;

	/*
	* In GuC mode of submission, the busyness stats may get updated after
	* the batch starts running. Poll for a change in busyness and timeout
	* after 500 us.
	*/
	start = ktime_get();
	while (intel_engine_get_busy_time(engine, &unused) == busyness) {
	dt = ktime_get() - start;
	if (dt > 10000000) {
	pr_err("active wait timed out %lld\n", dt);
	ENGINE_TRACE(engine, "active wait time out %lld\n", dt);
	return -ETIME;
	}
	}

	return 0;
	}

	static int live_engine_busy_stats(void *arg)
	{
	struct intel_gt *gt = arg;
	struct intel_engine_cs *engine;
	enum intel_engine_id id;
	struct igt_spinner spin;
	int err = 0;

	/*
	* Check that if an engine supports busy-stats, they tell the truth.
	*/

	if (igt_spinner_init(&spin, gt))
	return -ENOMEM;

	GEM_BUG_ON(intel_gt_pm_is_awake(gt));
	for_each_engine(engine, gt, id) {
	struct i915_request *rq;
	ktime_t busyness, dummy;
	ktime_t de, dt;
	ktime_t t[2];

	if (!intel_engine_supports_stats(engine))
	continue;

	if (!intel_engine_can_store_dword(engine))
	continue;

	if (intel_gt_pm_wait_for_idle(gt)) {
	err = -EBUSY;
	break;
	}

	st_engine_heartbeat_disable(engine);

	ENGINE_TRACE(engine, "measuring idle time\n");
	preempt_disable();
	de = intel_engine_get_busy_time(engine, &t[0]);
	udelay(100);
	de = ktime_sub(intel_engine_get_busy_time(engine, &t[1]), de);
	preempt_enable();
	dt = ktime_sub(t[1], t[0]);
	if (de < 0 \|\| de > 10) {
	pr_err("%s: reported %lldns [%d%%] busyness while sleeping [for %lldns]\n",
	engine->name,
	de, (int)div64_u64(100 * de, dt), dt);
	GEM_TRACE_DUMP();
	err = -EINVAL;
	goto end;
	}

	/* 100% busy */
	rq = igt_spinner_create_request(&spin,
	engine->kernel_context,
	MI_NOOP);
	if (IS_ERR(rq)) {
	err = PTR_ERR(rq);
	goto end;
	}
	i915_request_add(rq);

	busyness = intel_engine_get_busy_time(engine, &dummy);
	if (!igt_wait_for_spinner(&spin, rq)) {
	intel_gt_set_wedged(engine->gt);
	err = -ETIME;
	goto end;
	}

	err = __spin_until_busier(engine, busyness);
	if (err) {
	GEM_TRACE_DUMP();
	goto end;
	}

	ENGINE_TRACE(engine, "measuring busy time\n");
	preempt_disable();
	de = intel_engine_get_busy_time(engine, &t[0]);
	mdelay(100);
	de = ktime_sub(intel_engine_get_busy_time(engine, &t[1]), de);
	preempt_enable();
	dt = ktime_sub(t[1], t[0]);
	if (100 * de < 95 * dt \|\| 95 * de > 100 * dt) {
	pr_err("%s: reported %lldns [%d%%] busyness while spinning [for %lldns]\n",
	engine->name,
	de, (int)div64_u64(100 * de, dt), dt);
	GEM_TRACE_DUMP();
	err = -EINVAL;
	goto end;
	}

	end:
	st_engine_heartbeat_enable(engine);
	igt_spinner_end(&spin);
	if (igt_flush_test(gt->i915))
	err = -EIO;
	if (err)
	break;
	}

	igt_spinner_fini(&spin);
	if (igt_flush_test(gt->i915))
	err = -EIO;
	return err;
	}

	static int live_engine_pm(void *arg)
	{
	struct intel_gt *gt = arg;
	struct intel_engine_cs *engine;
	enum intel_engine_id id;

	/*
	* Check we can call intel_engine_pm_put from any context. No
	* failures are reported directly, but if we mess up lockdep should
	* tell us.
	*/
	if (intel_gt_pm_wait_for_idle(gt)) {
	pr_err("Unable to flush GT pm before test\n");
	return -EBUSY;
	}

	GEM_BUG_ON(intel_gt_pm_is_awake(gt));
	for_each_engine(engine, gt, id) {
	const typeof(igt_atomic_phases) p;

	for (p = igt_atomic_phases; p->name; p++) {
	/*
	* Acquisition is always synchronous, except if we
	* know that the engine is already awake, in which
	* case we should use intel_engine_pm_get_if_awake()
	* to atomically grab the wakeref.
	*
	* In practice,
	* intel_engine_pm_get();
	* intel_engine_pm_put();
	* occurs in one thread, while simultaneously
	* intel_engine_pm_get_if_awake();
	* intel_engine_pm_put();
	* occurs from atomic context in another.
	*/
	GEM_BUG_ON(intel_engine_pm_is_awake(engine));
	intel_engine_pm_get(engine);

	p->critical_section_begin();
	if (!intel_engine_pm_get_if_awake(engine))
	pr_err("intel_engine_pm_get_if_awake(%s) failed under %s\n",
	engine->name, p->name);
	else
	intel_engine_pm_put_async(engine);
	intel_engine_pm_put_async(engine);
	p->critical_section_end();

	intel_engine_pm_flush(engine);

	if (intel_engine_pm_is_awake(engine)) {
	pr_err("%s is still awake after flushing pm\n",
	engine->name);
	return -EINVAL;
	}

	/* gt wakeref is async (deferred to workqueue) */
	if (intel_gt_pm_wait_for_idle(gt)) {
	gt_err(gt, "GT failed to idle\n");
	return -EINVAL;
	}
	}
	}

	return 0;
	}

	int live_engine_pm_selftests(struct intel_gt *gt)
	{
	static const struct i915_subtest tests[] = {
	SUBTEST(live_engine_timestamps),
	SUBTEST(live_engine_busy_stats),
	SUBTEST(live_engine_pm),
	};

	return intel_gt_live_subtests(tests, gt);
	}