[Intel-gfx] [PATCH] drm/i915/selftests: Force a failed engine reset

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> Inject a fault into the engine reset and check that the outstanding
> requests are completed despite the failed reset.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/gt/selftest_hangcheck.c | 133 +++++++++++++++++++
>  1 file changed, 133 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> index ffc6eabb6404..875633cc0a75 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> @@ -540,6 +540,138 @@ static int igt_reset_nop_engine(void *arg)
>  	return 0;
>  }
>  
> +static void force_reset_timeout(struct intel_engine_cs *engine)
> +{
> +	engine->reset_timeout.probability = 999;
> +	atomic_set(&engine->reset_timeout.times, -1);
> +}
> +
> +static void cancel_reset_timeout(struct intel_engine_cs *engine)
> +{
> +	memset(&engine->reset_timeout, 0, sizeof(engine->reset_timeout));
> +}
> +
> +static int igt_reset_fail_engine(void *arg)
> +{
> +	struct intel_gt *gt = arg;
> +	struct intel_engine_cs *engine;
> +	enum intel_engine_id id;
> +
> +	/* Check that we can engine-reset during non-user portions */
> +
> +	if (!intel_has_reset_engine(gt))
> +		return 0;
> +
> +	for_each_engine(engine, gt, id) {
> +		unsigned int count;
> +		struct intel_context *ce;
> +		IGT_TIMEOUT(end_time);
> +		int err;
> +
> +		ce = intel_context_create(engine);
> +		if (IS_ERR(ce))
> +			return PTR_ERR(ce);
> +
> +		st_engine_heartbeat_disable(engine);
> +		set_bit(I915_RESET_ENGINE + id, &gt->reset.flags);
> +		count = 0;
> +		do {
> +			struct i915_request *last = NULL;
> +			int i;
> +
> +			if (!wait_for_idle(engine)) {
> +				pr_err("%s failed to idle before reset\n",
> +				       engine->name);
> +				err = -EIO;
> +				break;
> +			}
> +
> +			for (i = 0; i < 16; i++) {
> +				struct i915_request *rq;
> +
> +				rq = intel_context_create_request(ce);
> +				if (IS_ERR(rq)) {
> +					struct drm_printer p =
> +						drm_info_printer(gt->i915->drm.dev);
> +					intel_engine_dump(engine, &p,
> +							  "%s(%s): failed to submit request\n",
> +							  __func__,
> +							  engine->name);
> +
> +					GEM_TRACE("%s(%s): failed to submit request\n",
> +						  __func__,
> +						  engine->name);
> +					GEM_TRACE_DUMP();
> +
> +					intel_gt_set_wedged(gt);
> +					if (last)
> +						i915_request_put(last);
> +
> +					err = PTR_ERR(rq);
> +					goto out;
> +				}
> +
> +				if (last)
> +					i915_request_put(last);
> +				last = i915_request_get(rq);
> +				i915_request_add(rq);
> +			}
> +
> +			if (count & 1) {
> +				err = intel_engine_reset(engine, NULL);
> +				if (err) {
> +					GEM_TRACE_ERR("intel_engine_reset(%s) failed, err:%d\n",
> +						      engine->name, err);
> +					GEM_TRACE_DUMP();
> +					break;
> +				}
> +			} else {
> +				force_reset_timeout(engine);
> +				err = intel_engine_reset(engine, NULL);

We dont promote to global here if the engine one fails?

If not, what mechanism then guarantees the request completion.

-Mika

> +				cancel_reset_timeout(engine);
> +				if (err != -ETIMEDOUT) {
> +					pr_err("intel_engine_reset(%s) did not fail, err:%d\n",
> +					       engine->name, err);
> +					break;
> +				}
> +			}
> +
> +			err = 0;
> +			if (i915_request_wait(last, 0, HZ /2) < 0) {
> +				struct drm_printer p =
> +					drm_info_printer(gt->i915->drm.dev);
> +
> +				intel_engine_dump(engine, &p,
> +						  "%s(%s): failed to complete request\n",
> +						  __func__,
> +						  engine->name);
> +
> +				GEM_TRACE("%s(%s): failed to complete request\n",
> +					  __func__,
> +					  engine->name);
> +				GEM_TRACE_DUMP();
> +
> +				err = -EIO;
> +			}
> +			i915_request_put(last);
> +			count++;
> +		} while (err == 0 && time_before(jiffies, end_time));
> +out:
> +		clear_bit(I915_RESET_ENGINE + id, &gt->reset.flags);
> +		st_engine_heartbeat_enable(engine);
> +
> +		pr_info("%s(%s): %d resets\n", __func__, engine->name, count);
> +
> +		intel_context_put(ce);
> +		if (igt_flush_test(gt->i915))
> +			err = -EIO;
> +		if (err)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +
>  static int __igt_reset_engine(struct intel_gt *gt, bool active)
>  {
>  	struct i915_gpu_error *global = &gt->i915->gpu_error;
> @@ -1694,6 +1826,7 @@ int intel_hangcheck_live_selftests(struct drm_i915_private *i915)
>  		SUBTEST(igt_reset_nop_engine),
>  		SUBTEST(igt_reset_idle_engine),
>  		SUBTEST(igt_reset_active_engine),
> +		SUBTEST(igt_reset_fail_engine),
>  		SUBTEST(igt_reset_engines),
>  		SUBTEST(igt_reset_engines_atomic),
>  		SUBTEST(igt_reset_queue),
> -- 
> 2.20.1
>
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