[Intel-gfx] [PATCH] drm/i915/selftests: Move test flush to outside vm->mutex

[Chris Wilson]

Quoting Tvrtko Ursulin (2020-06-12 15:44:51)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> As per our locking rules it is not allowed to wait on requests while
> holding locks. In this case we were trying to idle the GPU while holding
> the vm->mutex.

Synchronous eviction would like to have a word.

> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>  drivers/gpu/drm/i915/selftests/i915_gem_evict.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_evict.c b/drivers/gpu/drm/i915/selftests/i915_gem_evict.c
> index 028baae9631f..67f4497c8224 100644
> --- a/drivers/gpu/drm/i915/selftests/i915_gem_evict.c
> +++ b/drivers/gpu/drm/i915/selftests/i915_gem_evict.c
> @@ -498,8 +498,6 @@ static int igt_evict_contexts(void *arg)
>  
>         mutex_lock(&ggtt->vm.mutex);
>  out_locked:
> -       if (igt_flush_test(i915))
> -               err = -EIO;
>         while (reserved) {
>                 struct reserved *next = reserved->next;
>  
> @@ -513,6 +511,9 @@ static int igt_evict_contexts(void *arg)
>         mutex_unlock(&ggtt->vm.mutex);
>         intel_runtime_pm_put(&i915->runtime_pm, wakeref);
>  
> +       if (igt_flush_test(i915))
> +               err = -EIO;

The patch is ok, since the manual drm_mm_node reservations are not used
by the GTT, but the reason is a bit specious.
-Chris