From e9808edd98679680804dfbc42c5ee8f1aa91f617 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 4 Jul 2012 12:25:08 +0100
Subject: [PATCH] drm/i915: Return a mask of the active rings in the high word
 of busy_ioctl

The intention is to help select which engine to use for copies with
interoperating clients - such as a GL client making a request to the X
server to perform a SwapBuffers, which may require copying from the
active GL back buffer to the X front buffer.

We choose to report a mask of the active rings to future proof the
interface against any changes which may allow for the object to reside
upon multiple rings.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: bikeshed away the write ring mask and add the explanation
Chris sent in a follow-up mail why we decided to use masks.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem.c | 4 ++++
 include/drm/i915_drm.h          | 6 +++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 5c4657a54f97..4be096068b35 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3400,6 +3400,10 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
 	ret = i915_gem_object_flush_active(obj);
 
 	args->busy = obj->active;
+	if (obj->ring) {
+		BUILD_BUG_ON(I915_NUM_RINGS > 16);
+		args->busy |= intel_ring_flag(obj->ring) << 16;
+	}
 
 	drm_gem_object_unreference(&obj->base);
 unlock:
diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index b923b032743f..0f149fe32211 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -704,7 +704,11 @@ struct drm_i915_gem_busy {
 	/** Handle of the buffer to check for busy */
 	__u32 handle;
 
-	/** Return busy status (1 if busy, 0 if idle) */
+	/** Return busy status (1 if busy, 0 if idle).
+	 * The high word is used to indicate on which rings the object
+	 * currently resides:
+	 *  16:31 - busy (r or r/w) rings (16 render, 17 bsd, 18 blt, etc)
+	 */
 	__u32 busy;
 };
 
-- 
2.30.9