drm/i915: swizzling support for snb/ivb
We have to do this manually. Somebody had a Great Idea.
I've measured speed-ups just a few percent above the noise level
(below 5% for the best case), but no slowdows. Chris Wilson measured
quite a bit more (10-20% above the usual snb variance) on a more
recent and better tuned version of sna, but also recorded a few
slow-downs on benchmarks know for uglier amounts of snb-induced
variance.
v2: Incorporate Ben Widawsky's preliminary review comments and
elaborate a bit about the performance impact in the changelog.
v3: Add a comment as to why we don't need to check the 3rd memory
channel.
v4: Fixup whitespace.
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
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 51a2b0c..86fffd2 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3681,12 +3681,31 @@
return 0;
}
+void i915_gem_init_swizzling(struct drm_device *dev)
+{
+ drm_i915_private_t *dev_priv = dev->dev_private;
+
+ if (INTEL_INFO(dev)->gen < 6 ||
+ dev_priv->mm.bit_6_swizzle_x == I915_BIT_6_SWIZZLE_NONE)
+ return;
+
+ I915_WRITE(DISP_ARB_CTL, I915_READ(DISP_ARB_CTL) |
+ DISP_TILE_SURFACE_SWIZZLING);
+
+ I915_WRITE(TILECTL, I915_READ(TILECTL) | TILECTL_SWZCTL);
+ if (IS_GEN6(dev))
+ I915_WRITE(ARB_MODE, ARB_MODE_ENABLE(ARB_MODE_SWIZZLE_SNB));
+ else
+ I915_WRITE(ARB_MODE, ARB_MODE_ENABLE(ARB_MODE_SWIZZLE_IVB));
+}
int
-i915_gem_init_ringbuffer(struct drm_device *dev)
+i915_gem_init_hw(struct drm_device *dev)
{
drm_i915_private_t *dev_priv = dev->dev_private;
int ret;
+ i915_gem_init_swizzling(dev);
+
ret = intel_init_render_ring_buffer(dev);
if (ret)
return ret;
@@ -3742,7 +3761,7 @@
mutex_lock(&dev->struct_mutex);
dev_priv->mm.suspended = 0;
- ret = i915_gem_init_ringbuffer(dev);
+ ret = i915_gem_init_hw(dev);
if (ret != 0) {
mutex_unlock(&dev->struct_mutex);
return ret;
