[Intel-gfx] [PATCH 13/53] drm/i915/bdw: Deferred creation of user-created LRCs

[oscar.mateo at intel.com]

From: Oscar Mateo <oscar.mateo at intel.com>

The backing objects for contexts created via open fd are actually
empty until the user starts sending execbuffers to them. We do this
because, at create time, we really don't know which engine is going
to be used with the context later on.

v2: As context created via ioctl can only be used with the render ring,
we have enough information to allocate & populate them right away.

Signed-off-by: Oscar Mateo <oscar.mateo at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_context.c | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 1fb4592..70bf6d0 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -795,6 +795,7 @@ static bool contexts_enabled(struct drm_device *dev)
 int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
 				  struct drm_file *file)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_context_create *args = data;
 	struct drm_i915_file_private *file_priv = file->driver_priv;
 	struct intel_context *ctx;
@@ -808,9 +809,23 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
 		return ret;
 
 	ctx = i915_gem_create_context(dev, file_priv, USES_FULL_PPGTT(dev));
-	mutex_unlock(&dev->struct_mutex);
-	if (IS_ERR(ctx))
+	if (IS_ERR(ctx)) {
+		mutex_unlock(&dev->struct_mutex);
 		return PTR_ERR(ctx);
+	}
+
+	if (dev_priv->lrc_enabled) {
+		/* NB: We know this context will only be used with the render ring
+		 * (as we enforce it) so we can allocate & populate it already */
+		int ret = intel_lr_context_deferred_create(ctx, &dev_priv->ring[RCS]);
+		if (ret) {
+			mutex_unlock(&dev->struct_mutex);
+			DRM_DEBUG_DRIVER("Could not create LRC: %d\n", ret);
+			return ret;
+		}
+	}
+
+	mutex_unlock(&dev->struct_mutex);
 
 	args->ctx_id = ctx->id;
 	DRM_DEBUG_DRIVER("HW context %d created\n", args->ctx_id);
@@ -851,6 +866,7 @@ struct intel_context *
 i915_gem_context_validate(struct drm_device *dev, struct drm_file *file,
 			  struct intel_engine_cs *ring, const u32 ctx_id)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_context *ctx = NULL;
 	struct i915_ctx_hang_stats *hs;
 
@@ -867,5 +883,13 @@ i915_gem_context_validate(struct drm_device *dev, struct drm_file *file,
 		return ERR_PTR(-EIO);
 	}
 
+	if (dev_priv->lrc_enabled && !ctx->engine[ring->id].obj) {
+		int ret = intel_lr_context_deferred_create(ctx, ring);
+		if (ret) {
+			DRM_DEBUG("Could not create LRC %u: %d\n", ctx_id, ret);
+			return ERR_PTR(ret);
+		}
+	}
+
 	return ctx;
 }
-- 
1.9.0