[PATCH v4 4/8] drm/i915: Adjust internal priority definitions

[Matt Roper]

In preparation for adding cgroup-based priority adjustments, let's
define the driver's priority values a little more clearly.

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h         |  1 -
 drivers/gpu/drm/i915/i915_gem_context.c |  4 ++--
 drivers/gpu/drm/i915/i915_request.h     | 13 ++++++++++---
 drivers/gpu/drm/i915/intel_display.c    |  2 +-
 4 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e27ba8fb64e6..6ce7d0662bb6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3150,7 +3150,6 @@ int i915_gem_object_wait(struct drm_i915_gem_object *obj,
 int i915_gem_object_wait_priority(struct drm_i915_gem_object *obj,
 				  unsigned int flags,
 				  int priority);
-#define I915_PRIORITY_DISPLAY I915_PRIORITY_MAX
 
 int __must_check
 i915_gem_object_set_to_wc_domain(struct drm_i915_gem_object *obj, bool write);
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 5cfac0255758..551c1d75fe24 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -474,7 +474,7 @@ int i915_gem_contexts_init(struct drm_i915_private *dev_priv)
 	ida_init(&dev_priv->contexts.hw_ida);
 
 	/* lowest priority; idle task */
-	ctx = i915_gem_context_create_kernel(dev_priv, I915_PRIORITY_MIN);
+	ctx = i915_gem_context_create_kernel(dev_priv, I915_PRIORITY_IDLE);
 	if (IS_ERR(ctx)) {
 		DRM_ERROR("Failed to create default global context\n");
 		return PTR_ERR(ctx);
@@ -488,7 +488,7 @@ int i915_gem_contexts_init(struct drm_i915_private *dev_priv)
 
 	/* highest priority; preempting task */
 	if (needs_preempt_context(dev_priv)) {
-		ctx = i915_gem_context_create_kernel(dev_priv, INT_MAX);
+		ctx = i915_gem_context_create_kernel(dev_priv, I915_PRIORITY_PREEMPT);
 		if (!IS_ERR(ctx))
 			dev_priv->preempt_context = ctx;
 		else
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 7d6eb82eeb91..72b13fc2b72b 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -78,12 +78,19 @@ struct i915_priotree {
 	int priority;
 };
 
+/*
+ * Userspace can only assign priority values of [-1023,1023] via context param,
+ * but the effective priority value can fall in a larger range once we add in
+ * a cgroup-provided offset.
+ */
 enum {
-	I915_PRIORITY_MIN = I915_CONTEXT_MIN_USER_PRIORITY - 1,
 	I915_PRIORITY_NORMAL = I915_CONTEXT_DEFAULT_PRIORITY,
-	I915_PRIORITY_MAX = I915_CONTEXT_MAX_USER_PRIORITY + 1,
+	I915_PRIORITY_DEFAULT_DISPBOOST = I915_CONTEXT_MAX_USER_PRIORITY + 1,
 
-	I915_PRIORITY_INVALID = INT_MIN
+	/* Special case priority values */
+	I915_PRIORITY_INVALID = INT_MIN,
+	I915_PRIORITY_IDLE = INT_MIN + 1,
+	I915_PRIORITY_PREEMPT = INT_MAX,
 };
 
 struct i915_capture_list {
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3e7ab75e1b41..b053a21f682b 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12783,7 +12783,7 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 
 	ret = intel_plane_pin_fb(to_intel_plane_state(new_state));
 
-	i915_gem_object_wait_priority(obj, 0, I915_PRIORITY_DISPLAY);
+	i915_gem_object_wait_priority(obj, 0, I915_PRIORITY_DEFAULT_DISPBOOST);
 
 	mutex_unlock(&dev_priv->drm.struct_mutex);
 	i915_gem_object_unpin_pages(obj);
-- 
2.14.3