drm/i915/guc: Disable semaphores when using GuC scheduling

Semaphores are an optimization and not required for basic GuC submission
to work properly. Disable until we have time to do the implementation to
enable semaphores and tune them for performance. Also long direction is
just to delete semaphores from the i915 so another reason to not enable
these for GuC submission.

This patch fixes an existing bugs where I915_ENGINE_HAS_SEMAPHORES was
not honored correctly.

v2: Reword commit message
v3:
 (John H)
  - Add text to commit indicating this also fixing an existing bug
v4:
 (John H)
  - s/bug/bugs

Cc: John Harrison <john.c.harrison@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721215101.139794-14-matthew.brost@intel.com

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index bf2a2319353a44bf33decddd02fd89bd2c5f8e9c..89ca401bf9ae5cf77e7e10dd4f8607718561ce1a 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -799,7 +799,8 @@ static int intel_context_set_gem(struct intel_context *ce,
        }
 
        if (ctx->sched.priority >= I915_PRIORITY_NORMAL &&
-           intel_engine_has_timeslices(ce->engine))
+           intel_engine_has_timeslices(ce->engine) &&
+           intel_engine_has_semaphores(ce->engine))
                __set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags);
 
        if (IS_ACTIVE(CONFIG_DRM_I915_REQUEST_TIMEOUT) &&
@@ -1778,7 +1779,8 @@ static void __apply_priority(struct intel_context *ce, void *arg)
        if (!intel_engine_has_timeslices(ce->engine))
                return;
 
-       if (ctx->sched.priority >= I915_PRIORITY_NORMAL)
+       if (ctx->sched.priority >= I915_PRIORITY_NORMAL &&
+           intel_engine_has_semaphores(ce->engine))
                intel_context_set_use_semaphores(ce);
        else
                intel_context_clear_use_semaphores(ce);