[igt-dev] [Intel-gfx] [PATCH i-g-t 4/4] tests/gem_media_vme: Shut down half of subslices to avoid gpu hang on ICL

[Chris Wilson]

Quoting Tvrtko Ursulin (2018-12-13 12:06:36)
> +static void shut_non_vme_subslices(int drm_fd, uint32_t ctx)
> +{
> +       struct drm_i915_gem_context_param_sseu sseu = { };
> +       struct drm_i915_gem_context_param arg = {
> +               .param = I915_CONTEXT_PARAM_SSEU,
> +               .ctx_id = ctx,
> +               .size = sizeof(sseu),
> +               .value = to_user_pointer(&sseu),
> +       };
> +       int ret;
> +
> +       if (__gem_context_get_param(drm_fd, &arg))
> +               return; /* no sseu support */
> +
> +       ret = __gem_context_set_param(drm_fd, &arg);
> +       igt_assert(ret == 0 || ret == -ENODEV || ret == -EINVAL);
> +       if (ret)
> +               return; /* no sseu support */

/* no sseu reconfiguration */

That justifies for me the two step is-supported check.
get -> does the kernel recognise this param and do we have sseu
set -> does the kernel/device allow us to adjust sseu
-Chris