drm/i915: announce to userspace that the bsd ring is coherent

Otherwise we can't really fix the abi-braindeadness of forcing
libva to manually wait for rendering when switching rings. Which
in turn makes implementing hw semaphores a pointless exercise
(at least for ironlake).

[Also added the relaxed fencing param to explain the jump in
numbering - relaxed fencing is in -next.]

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 7a26f4dd21ae..e6800819bca8 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -767,6 +767,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
         case I915_PARAM_HAS_BLT:
                 value = HAS_BLT(dev);
                 break;
+        case I915_PARAM_HAS_COHERENT_RINGS:
+                value = 1;
+                break;
         default:
                 DRM_DEBUG_DRIVER("Unknown parameter %d\n",
                                  param->param);