drm/i915/bdw: Don't execute context reset and switch with Execlists

These two functions make no sense in an Logical Ring Context & Execlists
world.

v2: We got rid of lrc_enabled and centralized everything in the sanitized
i915.enable_execlists instead.

Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
v3: Rebased.  Corrected a typo in comment for i915_switch_context and
added a comment that it should not be called in execlist mode. Added
WARN_ON if i915_switch_context is called in execlist mode. Moved check
for execlist mode out of i915_switch_context and into callers. Added
comment in context_reset explaining why nothing is done in execlist
mode.

Signed-off-by: Thomas Daniel <thomas.daniel@intel.com>
[danvet: Simplify the patch subject so I can understand it.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index fcd7dde6e44440c7e71528e31cd3f0df799ba9a2..60b8bd1717dbaf02b51ae901dcfbe941559d6c6a 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2985,9 +2985,11 @@ int i915_gpu_idle(struct drm_device *dev)
 
        /* Flush everything onto the inactive list. */
        for_each_ring(ring, dev_priv, i) {
-               ret = i915_switch_context(ring, ring->default_context);
-               if (ret)
-                       return ret;
+               if (!i915.enable_execlists) {
+                       ret = i915_switch_context(ring, ring->default_context);
+                       if (ret)
+                               return ret;
+               }
 
                ret = intel_ring_idle(ring);
                if (ret)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index afe78fd0db29ff8fce1687942822f0033aa0323d..62ee178b1edb0dc2750dbb86b2de36dfca26bc71 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -289,6 +289,12 @@ void i915_gem_context_reset(struct drm_device *dev)
        struct drm_i915_private *dev_priv = dev->dev_private;
        int i;
 
+       /* In execlists mode we will unreference the context when the execlist
+        * queue is cleared and the requests destroyed.
+        */
+       if (i915.enable_execlists)
+               return;
+
        for (i = 0; i < I915_NUM_RINGS; i++) {
                struct intel_engine_cs *ring = &dev_priv->ring[i];
                struct intel_context *lctx = ring->last_context;
@@ -397,6 +403,9 @@ int i915_gem_context_enable(struct drm_i915_private *dev_priv)
 
        BUG_ON(!dev_priv->ring[RCS].default_context);
 
+       if (i915.enable_execlists)
+               return 0;
+
        for_each_ring(ring, dev_priv, i) {
                ret = i915_switch_context(ring, ring->default_context);
                if (ret)
@@ -639,14 +648,19 @@ unpin_out:
  *
  * The context life cycle is simple. The context refcount is incremented and
  * decremented by 1 and create and destroy. If the context is in use by the GPU,
- * it will have a refoucnt > 1. This allows us to destroy the context abstract
+ * it will have a refcount > 1. This allows us to destroy the context abstract
  * object while letting the normal object tracking destroy the backing BO.
+ *
+ * This function should not be used in execlists mode.  Instead the context is
+ * switched by writing to the ELSP and requests keep a reference to their
+ * context.
  */
 int i915_switch_context(struct intel_engine_cs *ring,
                        struct intel_context *to)
 {
        struct drm_i915_private *dev_priv = ring->dev->dev_private;
 
+       WARN_ON(i915.enable_execlists);
        WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));
 
        if (to->legacy_hw_ctx.rcs_state == NULL) { /* We have the fake context */