drm/i915: Install fence register for tiled scanout on i915
With the work by Jesse Barnes to eliminate allocation of fences during
execbuffer, it becomes possible to write to the scan-out buffer with it
never acquiring a fence (simply by only ever writing to the object using
tiled GPU commands and never writing to it via the GTT). So for pre-i965
chipsets which require fenced access for tiled scan-out buffers, we need
to obtain a fence register.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a5f95ad..4f34541 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -46,7 +46,6 @@
static int i915_gem_object_wait_rendering(struct drm_gem_object *obj);
static int i915_gem_object_bind_to_gtt(struct drm_gem_object *obj,
unsigned alignment);
-static int i915_gem_object_get_fence_reg(struct drm_gem_object *obj, bool write);
static void i915_gem_clear_fence_reg(struct drm_gem_object *obj);
static int i915_gem_evict_something(struct drm_device *dev);
static int i915_gem_phys_pwrite(struct drm_device *dev, struct drm_gem_object *obj,
@@ -1158,7 +1157,7 @@
/* Need a new fence register? */
if (obj_priv->fence_reg == I915_FENCE_REG_NONE &&
obj_priv->tiling_mode != I915_TILING_NONE) {
- ret = i915_gem_object_get_fence_reg(obj, write);
+ ret = i915_gem_object_get_fence_reg(obj);
if (ret) {
mutex_unlock(&dev->struct_mutex);
return VM_FAULT_SIGBUS;
@@ -2169,7 +2168,6 @@
/**
* i915_gem_object_get_fence_reg - set up a fence reg for an object
* @obj: object to map through a fence reg
- * @write: object is about to be written
*
* When mapping objects through the GTT, userspace wants to be able to write
* to them without having to worry about swizzling if the object is tiled.
@@ -2180,8 +2178,8 @@
* It then sets up the reg based on the object's properties: address, pitch
* and tiling format.
*/
-static int
-i915_gem_object_get_fence_reg(struct drm_gem_object *obj, bool write)
+int
+i915_gem_object_get_fence_reg(struct drm_gem_object *obj)
{
struct drm_device *dev = obj->dev;
struct drm_i915_private *dev_priv = dev->dev_private;
@@ -3550,7 +3548,7 @@
if (!IS_I965G(dev) &&
obj_priv->fence_reg == I915_FENCE_REG_NONE &&
obj_priv->tiling_mode != I915_TILING_NONE) {
- ret = i915_gem_object_get_fence_reg(obj, true);
+ ret = i915_gem_object_get_fence_reg(obj);
if (ret != 0) {
if (ret != -EBUSY && ret != -ERESTARTSYS)
DRM_ERROR("Failure to install fence: %d\n",