On Fri, Mar 01, 2024 at 12:28:57AM +0100, Andi Shyti wrote:
> Some of the CCS engines are disabled. They should not be listed
> in the uabi_engine list, that is the list of engines that the
> user can see.
Fused off engines already aren't visible to userspace (or to the kernel
for that matter). For CCS engines engine_mask_apply_compute_fuses()
removes the fused off engines from the runtime engine mask; other engine
types are handled in similar functions. Any engine that doesn't appear
in the filtered down engine_mask won't even have a 'struct
intel_engine_cs' allocated for it.
Matt
>
> Fixes: d2eae8e98d59 ("drm/i915/dg2: Drop force_probe requirement")
> Requires: 4e4f77d74878 ("drm/i915/gt: Refactor uabi engine class/instance list creation")
> Signed-off-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/intel_engine_user.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c
> index cf8f24ad88f6..ec5bcd1c1ec4 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_user.c
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c
> @@ -244,6 +244,18 @@ void intel_engines_driver_register(struct drm_i915_private *i915)
> if (uabi_class > I915_LAST_UABI_ENGINE_CLASS)
> continue;
>
> + /*
> + * If the CCS engine is fused off, the corresponding bit
> + * in the engine mask is disabled. Do not expose it
> + * to the user.
> + *
> + * By default at least one engine is enabled (check
> + * the engine_mask_apply_compute_fuses() function.
> + */
> + if (!(engine->gt->info.engine_mask &
> + BIT(_CCS(engine->uabi_instance))))
> + continue;
> +
> GEM_BUG_ON(uabi_class >=
> ARRAY_SIZE(i915->engine_uabi_class_count));
> i915->engine_uabi_class_count[uabi_class]++;
> --
> 2.43.0
>
--
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation
