[Intel-gfx] [PATCH 18/19] drm/i915: Check for unpin correctness.

[Maarten Lankhorst]

This forces a WARN_ON in a otherwise undebuggable path. When the
WARN_ON triggers we don't have a work item to unpin, which results
in a leak that triggers when the framebuffer is freed, much later on.

It's very hard to find the leak afterwards, so add some debugging for this case.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 9bf737f856c7..62c91171900a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13463,11 +13463,20 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 	struct intel_plane *intel_plane = to_intel_plane(plane);
 	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
 	struct drm_i915_gem_object *old_obj = intel_fb_obj(plane->state->fb);
+	struct drm_crtc *crtc = new_state->crtc ?: plane->state->crtc;
 	int ret = 0;
 
 	if (!obj && !old_obj)
 		return 0;
 
+	if (WARN_ON(!new_state->state) || WARN_ON(!crtc) ||
+	    WARN_ON(!to_intel_atomic_state(new_state->state)->work[to_intel_crtc(crtc)->pipe])) {
+		if (WARN_ON(old_obj != obj))
+			return -EINVAL;
+
+		return 0;
+	}
+
 	if (old_obj) {
 		struct drm_crtc_state *crtc_state =
 			drm_atomic_get_existing_crtc_state(new_state->state, plane->state->crtc);
-- 
2.1.0