drm/i915: Split idling from forcing context switch

We only need to force a switch to the kernel context placeholder during
eviction. All other uses of i915_gpu_idle() just want to wait until
existing work on the GPU is idle. Rename i915_gpu_idle() to
i915_gem_wait_for_idle() to avoid any implications about "parking" the
context first.

v2: Tweak an error message if the wait fails for the ilk vtd w/a

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466776558-21516-6-git-send-email-chris@chris-wilson.co.uk

1 files changed, 47 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index b144c3f..5741b58 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -33,6 +33,37 @@
 #include "intel_drv.h"
 #include "i915_trace.h"
 
+static int switch_to_pinned_context(struct drm_i915_private *dev_priv)
+{
+	struct intel_engine_cs *engine;
+
+	if (i915.enable_execlists)
+		return 0;
+
+	for_each_engine(engine, dev_priv) {
+		struct drm_i915_gem_request *req;
+		int ret;
+
+		if (engine->last_context == NULL)
+			continue;
+
+		if (engine->last_context == dev_priv->kernel_context)
+			continue;
+
+		req = i915_gem_request_alloc(engine, dev_priv->kernel_context);
+		if (IS_ERR(req))
+			return PTR_ERR(req);
+
+		ret = i915_switch_context(req);
+		i915_add_request_no_flush(req);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+
 static bool
 mark_free(struct i915_vma *vma, struct list_head *unwind)
 {
@@ -150,11 +181,17 @@ none:
 
 	/* Only idle the GPU and repeat the search once */
 	if (pass++ == 0) {
-		ret = i915_gpu_idle(dev);
+		struct drm_i915_private *dev_priv = to_i915(dev);
+
+		ret = switch_to_pinned_context(dev_priv);
 		if (ret)
 			return ret;
 
-		i915_gem_retire_requests(to_i915(dev));
+		ret = i915_gem_wait_for_idle(dev_priv);
+		if (ret)
+			return ret;
+
+		i915_gem_retire_requests(dev_priv);
 		goto search_again;
 	}
 
@@ -261,11 +298,17 @@ int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
 	trace_i915_gem_evict_vm(vm);
 
 	if (do_idle) {
-		ret = i915_gpu_idle(vm->dev);
+		struct drm_i915_private *dev_priv = to_i915(vm->dev);
+
+		ret = switch_to_pinned_context(dev_priv);
+		if (ret)
+			return ret;
+
+		ret = i915_gem_wait_for_idle(dev_priv);
 		if (ret)
 			return ret;
 
-		i915_gem_retire_requests(to_i915(vm->dev));
+		i915_gem_retire_requests(dev_priv);
 
 		WARN_ON(!list_empty(&vm->active_list));
 	}