[Intel-gfx] [PATCH 08/11] drm/i915: fixup i915_gem_evict_everything to actually evict everything

[Daniel Vetter]

Due to our not-so-optimal write-domain tracking, i915_gem_flush
is actually not sufficient to idle the gpu. When the gpu is actually
busy we most likely have a few bos with write_domain != 0 on the
active_list (why would the gpu be busy when not creating dirty bos?).
After the i915_wait_request these bos end up on the flushing_list.

I've left the BUG_ON I've used to prove my theory in there.

Therefore beef up i915_gpu_idle to first wait for any outstanding
rendering and then to flush everything and use this helper in
i915_gem_evict_everything.

This has the nice side-effect of potentially fixing s/r related
corruptions: Save when the bios somehow flushed gpu cashes for us
i915_gem_idle (the original user of i915_gpu_idle) suffered from the
same problem. Also move around i915_gpu_idle to avoid forward decls.

Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem.c |   69 +++++++++++++++++++++------------------
 1 files changed, 37 insertions(+), 32 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d8812ce..6bf4481 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2103,32 +2103,61 @@ i915_gem_find_inactive_object(struct drm_device *dev, int min_size)
 }
 
 static int
-i915_gem_evict_everything(struct drm_device *dev)
+i915_gpu_idle(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
+	bool lists_empty;
 	uint32_t seqno;
 	int ret;
-	bool lists_empty;
 
 	spin_lock(&dev_priv->mm.active_list_lock);
-	lists_empty = (list_empty(&dev_priv->mm.inactive_list) &&
-		       list_empty(&dev_priv->mm.flushing_list) &&
-		       list_empty(&dev_priv->mm.active_list));
+	lists_empty = list_empty(&dev_priv->mm.flushing_list) &&
+		      list_empty(&dev_priv->mm.active_list);
 	spin_unlock(&dev_priv->mm.active_list_lock);
 
 	if (lists_empty)
-		return -ENOSPC;
+		return 0;
 
-	/* Flush everything (on to the inactive lists) and evict */
-	i915_gem_flush(dev, I915_GEM_GPU_DOMAINS, I915_GEM_GPU_DOMAINS);
+	/* Wait for any outstanding rendering to complete ... */
 	seqno = i915_add_request(dev, NULL, I915_GEM_GPU_DOMAINS);
 	if (seqno == 0)
 		return -ENOMEM;
 
 	ret = i915_wait_request(dev, seqno);
+	if (ret != 0)
+		return ret;
+
+	/* ... and flush everything onto the inactive list. */
+	i915_gem_flush(dev, I915_GEM_GPU_DOMAINS, I915_GEM_GPU_DOMAINS);
+	seqno = i915_add_request(dev, NULL, I915_GEM_GPU_DOMAINS);
+	if (seqno == 0)
+		return -ENOMEM;
+
+	return i915_wait_request(dev, seqno);
+}
+
+static int
+i915_gem_evict_everything(struct drm_device *dev)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	int ret;
+	bool lists_empty;
+
+	spin_lock(&dev_priv->mm.active_list_lock);
+	lists_empty = (list_empty(&dev_priv->mm.inactive_list) &&
+		       list_empty(&dev_priv->mm.flushing_list) &&
+		       list_empty(&dev_priv->mm.active_list));
+	spin_unlock(&dev_priv->mm.active_list_lock);
+
+	if (lists_empty)
+		return -ENOSPC;
+
+	ret = i915_gpu_idle(dev);
 	if (ret)
 		return ret;
 
+	BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
+
 	ret = i915_gem_evict_from_inactive_list(dev);
 	if (ret)
 		return ret;
@@ -4455,30 +4484,6 @@ i915_gem_evict_from_inactive_list(struct drm_device *dev)
 	return 0;
 }
 
-static int
-i915_gpu_idle(struct drm_device *dev)
-{
-	drm_i915_private_t *dev_priv = dev->dev_private;
-	bool lists_empty;
-	uint32_t seqno;
-
-	spin_lock(&dev_priv->mm.active_list_lock);
-	lists_empty = list_empty(&dev_priv->mm.flushing_list) &&
-		      list_empty(&dev_priv->mm.active_list);
-	spin_unlock(&dev_priv->mm.active_list_lock);
-
-	if (lists_empty)
-		return 0;
-
-	/* Flush everything onto the inactive list. */
-	i915_gem_flush(dev, I915_GEM_GPU_DOMAINS, I915_GEM_GPU_DOMAINS);
-	seqno = i915_add_request(dev, NULL, I915_GEM_GPU_DOMAINS);
-	if (seqno == 0)
-		return -ENOMEM;
-
-	return i915_wait_request(dev, seqno);
-}
-
 int
 i915_gem_idle(struct drm_device *dev)
 {
-- 
1.6.6