drm/i915: implement fastpath for overlay flip waiting
As long as the gpu can keep up, neither the cpu (waiting for gpu)
nore the gpu (waiting for vblank to do an overlay flip) stalls.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
index 4e88abb..85e07e4 100644
--- a/drivers/gpu/drm/i915/intel_overlay.c
+++ b/drivers/gpu/drm/i915/intel_overlay.c
@@ -251,7 +251,6 @@
drm_i915_private_t *dev_priv = dev->dev_private;
u32 flip_addr = overlay->flip_addr;
u32 tmp;
- int ret;
RING_LOCALS;
BUG_ON(!overlay->active);
@@ -264,11 +263,40 @@
if (tmp & (1 << 17))
DRM_DEBUG("overlay underrun, DOVSTA: %x\n", tmp);
- BEGIN_LP_RING(6);
+ BEGIN_LP_RING(4);
OUT_RING(MI_FLUSH);
OUT_RING(MI_NOOP);
OUT_RING(MI_OVERLAY_FLIP | MI_OVERLAY_CONTINUE);
OUT_RING(flip_addr);
+ ADVANCE_LP_RING();
+
+ overlay->last_flip_req = i915_add_request(dev, NULL, 0);
+}
+
+static int intel_overlay_wait_flip(struct intel_overlay *overlay)
+{
+ struct drm_device *dev = overlay->dev;
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ int ret;
+ u32 tmp;
+ RING_LOCALS;
+
+ if (overlay->last_flip_req != 0) {
+ ret = i915_do_wait_request(dev, overlay->last_flip_req, 0);
+
+ if (ret != 0)
+ return ret;
+
+ overlay->last_flip_req = 0;
+
+ tmp = I915_READ(ISR);
+
+ if (!(tmp & I915_OVERLAY_PLANE_FLIP_PENDING_INTERRUPT))
+ return 0;
+ }
+
+ /* synchronous slowpath */
+ BEGIN_LP_RING(2);
OUT_RING(MI_WAIT_FOR_EVENT | MI_WAIT_FOR_OVERLAY_FLIP);
OUT_RING(MI_NOOP);
ADVANCE_LP_RING();
@@ -279,13 +307,8 @@
DRM_ERROR("intel overlay: ring sync failed, hw likely wedged\n");
overlay->hw_wedged = 1;
}
-}
-static int intel_overlay_wait_flip(struct intel_overlay *overlay)
-{
- /* don't overcomplicate things for now with asynchronous operations
- * see comment above */
- return 0;
+ return ret;
}
/* overlay needs to be disabled in OCMD reg */
@@ -344,7 +367,9 @@
return ret;
}
-/* wait for pending overlay flip and release old frame */
+/* Wait for pending overlay flip and release old frame.
+ * Needs to be called before the overlay register are changed
+ * via intel_overlay_(un)map_regs_atomic */
static int intel_overlay_release_old_vid(struct intel_overlay *overlay)
{
int ret;