[Intel-gfx] [PATCH 12/34] drm/i915: Issue engine resets onto idle engines

[John Harrison]

On 1/21/2019 14:20, Chris Wilson wrote:
> Always perform the requested reset, even if we believe the engine is
> idle. Presumably there was a reason the caller wanted the reset, and in
> the near future we lose the easy tracking for whether the engine is
> idle.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>   drivers/gpu/drm/i915/i915_reset.c             |  4 ----
>   .../gpu/drm/i915/selftests/intel_hangcheck.c  | 22 +++++--------------
>   2 files changed, 6 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reset.c b/drivers/gpu/drm/i915/i915_reset.c
> index 064fc6da1512..d44b095e2860 100644
> --- a/drivers/gpu/drm/i915/i915_reset.c
> +++ b/drivers/gpu/drm/i915/i915_reset.c
> @@ -1063,10 +1063,6 @@ int i915_reset_engine(struct intel_engine_cs *engine, const char *msg)
>   	GEM_TRACE("%s flags=%lx\n", engine->name, error->flags);
>   	GEM_BUG_ON(!test_bit(I915_RESET_ENGINE + engine->id, &error->flags));
>   
> -	if (i915_seqno_passed(intel_engine_get_seqno(engine),
> -			      intel_engine_last_submit(engine)))
> -		return 0;
> -
>   	reset_prepare_engine(engine);
>   
>   	if (msg)
> diff --git a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
> index 8025c7e0bf6c..2c38ea5892d9 100644
> --- a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
> +++ b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
> @@ -449,8 +449,6 @@ static int __igt_reset_engine(struct drm_i915_private *i915, bool active)
>   
>   		set_bit(I915_RESET_ENGINE + id, &i915->gpu_error.flags);
>   		do {
> -			u32 seqno = intel_engine_get_seqno(engine);
> -
>   			if (active) {
>   				struct i915_request *rq;
>   
> @@ -479,8 +477,6 @@ static int __igt_reset_engine(struct drm_i915_private *i915, bool active)
>   					break;
>   				}
>   
> -				GEM_BUG_ON(!rq->global_seqno);
> -				seqno = rq->global_seqno - 1;
AFAICT this saved seqno value was never used anyway? It only exists 
inside the loop, was only used in a pr_err earlier in the loop, and the 
start of the loop always (re-)initialises it. Or am I missing some 
hidden macro magic somewhere?


>   				i915_request_put(rq);
>   			}
>   
> @@ -496,11 +492,10 @@ static int __igt_reset_engine(struct drm_i915_private *i915, bool active)
>   				break;
>   			}
>   
> -			reset_engine_count += active;
>   			if (i915_reset_engine_count(&i915->gpu_error, engine) !=
> -			    reset_engine_count) {
> -				pr_err("%s engine reset %srecorded!\n",
> -				       engine->name, active ? "not " : "");
> +			    ++reset_engine_count) {
> +				pr_err("%s engine reset not recorded!\n",
> +				       engine->name);
>   				err = -EINVAL;
>   				break;
>   			}
> @@ -728,7 +723,6 @@ static int __igt_reset_engines(struct drm_i915_private *i915,
>   
>   		set_bit(I915_RESET_ENGINE + id, &i915->gpu_error.flags);
>   		do {
> -			u32 seqno = intel_engine_get_seqno(engine);
>   			struct i915_request *rq = NULL;
>   
>   			if (flags & TEST_ACTIVE) {
> @@ -756,9 +750,6 @@ static int __igt_reset_engines(struct drm_i915_private *i915,
>   					err = -EIO;
>   					break;
>   				}
> -
> -				GEM_BUG_ON(!rq->global_seqno);
> -				seqno = rq->global_seqno - 1;
>   			}
>   
>   			err = i915_reset_engine(engine, NULL);
> @@ -795,10 +786,9 @@ static int __igt_reset_engines(struct drm_i915_private *i915,
>   
>   		reported = i915_reset_engine_count(&i915->gpu_error, engine);
>   		reported -= threads[engine->id].resets;
> -		if (reported != (flags & TEST_ACTIVE ? count : 0)) {
> -			pr_err("i915_reset_engine(%s:%s): reset %lu times, but reported %lu, expected %lu reported\n",
> -			       engine->name, test_name, count, reported,
> -			       (flags & TEST_ACTIVE ? count : 0));
> +		if (reported != count) {
> +			pr_err("i915_reset_engine(%s:%s): reset %lu times, but reported %lu\n",
> +			       engine->name, test_name, count, reported);
>   			if (!err)
>   				err = -EINVAL;
>   		}

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