Re: [PATCH 1/2] drm/i915/selftests: Add a cancel request selftest that triggers a reset

[John Harrison <john.c.harrison@intel.com>]

On 1/13/2022 10:13, Matthew Brost wrote:
> Add a cancel request selftest that results in an engine reset to cancel
> the request as it is non-preemptable. Also insert a NOP request after
> the cancelled request and confirm that it completes successfully.
>
> v2:
>   (Tvrtko)
>    - Skip test if preemption timeout compiled out
>    - Skip test if engine reset isn't supported
>    - Update debug prints to be more descriptive
> v3:
>    - Add comment explaining test
> v4:
>   (John Harrison)
>    - Fix typos in comment explaining test
>    - goto out_rq is NOP creation fails
>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
>
> ---
>   drivers/gpu/drm/i915/selftests/i915_request.c | 117 ++++++++++++++++++
>   1 file changed, 117 insertions(+)
> ---
>   drivers/gpu/drm/i915/selftests/i915_request.c | 117 ++++++++++++++++++
>   1 file changed, 117 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/selftests/i915_request.c b/drivers/gpu/drm/i915/selftests/i915_request.c
> index 7f66f6d299b26..2a99dd7c2fe8a 100644
> --- a/drivers/gpu/drm/i915/selftests/i915_request.c
> +++ b/drivers/gpu/drm/i915/selftests/i915_request.c
> @@ -782,6 +782,115 @@ static int __cancel_completed(struct intel_engine_cs *engine)
>   	return err;
>   }
>   
> +/*
> + * Test to prove a non-preemptable request can be cancelled and a subsequent
Oops - another 'preemptible'. Maybe fix that one during merge?

Reviewed-by: John Harrison <John.C.Harrison@Intel.com>


> + * request on the same context can successfully complete after cancellation.
> + *
> + * Testing methodology is to create a non-preemptible request and submit it,
> + * wait for spinner to start, create a NOP request and submit it, cancel the
> + * spinner, wait for spinner to complete and verify it failed with an error,
> + * finally wait for NOP request to complete verify it succeeded without an
> + * error. Preemption timeout also reduced / restored so test runs in a timely
> + * maner.
> + */
> +static int __cancel_reset(struct drm_i915_private *i915,
> +			  struct intel_engine_cs *engine)
> +{
> +	struct intel_context *ce;
> +	struct igt_spinner spin;
> +	struct i915_request *rq, *nop;
> +	unsigned long preempt_timeout_ms;
> +	int err = 0;
> +
> +	if (!CONFIG_DRM_I915_PREEMPT_TIMEOUT ||
> +	    !intel_has_reset_engine(engine->gt))
> +		return 0;
> +
> +	preempt_timeout_ms = engine->props.preempt_timeout_ms;
> +	engine->props.preempt_timeout_ms = 100;
> +
> +	if (igt_spinner_init(&spin, engine->gt))
> +		goto out_restore;
> +
> +	ce = intel_context_create(engine);
> +	if (IS_ERR(ce)) {
> +		err = PTR_ERR(ce);
> +		goto out_spin;
> +	}
> +
> +	rq = igt_spinner_create_request(&spin, ce, MI_NOOP);
> +	if (IS_ERR(rq)) {
> +		err = PTR_ERR(rq);
> +		goto out_ce;
> +	}
> +
> +	pr_debug("%s: Cancelling active non-preemptable request\n",
> +		 engine->name);
> +	i915_request_get(rq);
> +	i915_request_add(rq);
> +	if (!igt_wait_for_spinner(&spin, rq)) {
> +		struct drm_printer p = drm_info_printer(engine->i915->drm.dev);
> +
> +		pr_err("Failed to start spinner on %s\n", engine->name);
> +		intel_engine_dump(engine, &p, "%s\n", engine->name);
> +		err = -ETIME;
> +		goto out_rq;
> +	}
> +
> +	nop = intel_context_create_request(ce);
> +	if (IS_ERR(nop))
> +		goto out_rq;
> +	i915_request_get(nop);
> +	i915_request_add(nop);
> +
> +	i915_request_cancel(rq, -EINTR);
> +
> +	if (i915_request_wait(rq, 0, HZ) < 0) {
> +		struct drm_printer p = drm_info_printer(engine->i915->drm.dev);
> +
> +		pr_err("%s: Failed to cancel hung request\n", engine->name);
> +		intel_engine_dump(engine, &p, "%s\n", engine->name);
> +		err = -ETIME;
> +		goto out_nop;
> +	}
> +
> +	if (rq->fence.error != -EINTR) {
> +		pr_err("%s: fence not cancelled (%u)\n",
> +		       engine->name, rq->fence.error);
> +		err = -EINVAL;
> +		goto out_nop;
> +	}
> +
> +	if (i915_request_wait(nop, 0, HZ) < 0) {
> +		struct drm_printer p = drm_info_printer(engine->i915->drm.dev);
> +
> +		pr_err("%s: Failed to complete nop request\n", engine->name);
> +		intel_engine_dump(engine, &p, "%s\n", engine->name);
> +		err = -ETIME;
> +		goto out_nop;
> +	}
> +
> +	if (nop->fence.error != 0) {
> +		pr_err("%s: Nop request errored (%u)\n",
> +		       engine->name, nop->fence.error);
> +		err = -EINVAL;
> +	}
> +
> +out_nop:
> +	i915_request_put(nop);
> +out_rq:
> +	i915_request_put(rq);
> +out_ce:
> +	intel_context_put(ce);
> +out_spin:
> +	igt_spinner_fini(&spin);
> +out_restore:
> +	engine->props.preempt_timeout_ms = preempt_timeout_ms;
> +	if (err)
> +		pr_err("%s: %s error %d\n", __func__, engine->name, err);
> +	return err;
> +}
> +
>   static int live_cancel_request(void *arg)
>   {
>   	struct drm_i915_private *i915 = arg;
> @@ -814,6 +923,14 @@ static int live_cancel_request(void *arg)
>   			return err;
>   		if (err2)
>   			return err2;
> +
> +		/* Expects reset so call outside of igt_live_test_* */
> +		err = __cancel_reset(i915, engine);
> +		if (err)
> +			return err;
> +
> +		if (igt_flush_test(i915))
> +			return -EIO;
>   	}
>   
>   	return 0;