Re: [PATCH 3/6] drm/i915/selftests: Fixup atomic reset checking

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

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

> We require that the intel_gpu_reset() was atomic, not the whole of
> i915_reset() which is guarded by a mutex. However, we do require that
> i915_reset_engine() is atomic for use from within the submission tasklet.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/gt/selftest_reset.c | 65 +++++++++++++++++++++++-
>  1 file changed, 63 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/selftest_reset.c b/drivers/gpu/drm/i915/gt/selftest_reset.c
> index 64c2c8ab64ec..641cf3aee8d5 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_reset.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_reset.c
> @@ -73,11 +73,13 @@ static int igt_atomic_reset(void *arg)
>  	for (p = igt_atomic_phases; p->name; p++) {
>  		GEM_TRACE("intel_gpu_reset under %s\n", p->name);
>  
> -		p->critical_section_begin();
>  		reset_prepare(i915);
> +		p->critical_section_begin();
> +
>  		err = intel_gpu_reset(i915, ALL_ENGINES);
> -		reset_finish(i915);
> +
>  		p->critical_section_end();
> +		reset_finish(i915);
>  
>  		if (err) {
>  			pr_err("intel_gpu_reset failed under %s\n", p->name);
> @@ -95,12 +97,71 @@ static int igt_atomic_reset(void *arg)
>  	return err;
>  }
>  
> +static int igt_atomic_engine_reset(void *arg)
> +{
> +	struct drm_i915_private *i915 = arg;
> +	const typeof(*igt_atomic_phases) *p;

I did admire the nastyness of this array.

> +	struct intel_engine_cs *engine;
> +	enum intel_engine_id id;
> +	int err = 0;
> +
> +	/* Check that the resets are usable from atomic context */
> +
> +	if (!intel_has_reset_engine(i915))
> +		return 0;
> +
> +	if (USES_GUC_SUBMISSION(i915))
> +		return 0;
> +
> +	intel_gt_pm_get(&i915->gt);
> +	igt_global_reset_lock(i915);
> +
> +	/* Flush any requests before we get started and check basics */
> +	if (!igt_force_reset(i915))
> +		goto out_unlock;

I would still go out with error if the prerequisites
are not met?

-Mika

> +
> +	for_each_engine(engine, i915, id) {
> +		tasklet_disable_nosync(&engine->execlists.tasklet);
> +		intel_engine_pm_get(engine);
> +
> +		for (p = igt_atomic_phases; p->name; p++) {
> +			GEM_TRACE("i915_reset_engine(%s) under %s\n",
> +				  engine->name, p->name);
> +
> +			p->critical_section_begin();
> +			err = i915_reset_engine(engine, NULL);
> +			p->critical_section_end();
> +
> +			if (err) {
> +				pr_err("i915_reset_engine(%s) failed under %s\n",
> +				       engine->name, p->name);
> +				break;
> +			}
> +		}
> +
> +		intel_engine_pm_put(engine);
> +		tasklet_enable(&engine->execlists.tasklet);
> +		if (err)
> +			break;
> +	}
> +
> +	/* As we poke around the guts, do a full reset before continuing. */
> +	igt_force_reset(i915);
> +
> +out_unlock:
> +	igt_global_reset_unlock(i915);
> +	intel_gt_pm_put(&i915->gt);
> +
> +	return err;
> +}
> +
>  int intel_reset_live_selftests(struct drm_i915_private *i915)
>  {
>  	static const struct i915_subtest tests[] = {
>  		SUBTEST(igt_global_reset), /* attempt to recover GPU first */
>  		SUBTEST(igt_wedged_reset),
>  		SUBTEST(igt_atomic_reset),
> +		SUBTEST(igt_atomic_engine_reset),
>  	};
>  	intel_wakeref_t wakeref;
>  	int err = 0;
> -- 
> 2.20.1
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