nvc0: reset the instanced elements state when doing blit using 3d engine

Since we update num_vtxelts here, we could otherwise end up with stale
instancing information in the upper bits which wouldn't otherwise get
reset. (Also we run the risk of the previous draw having set the first
element as instanced.)

This appears as one of the causes for the test pointed out in fdo#90363
to fail on nvc0.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90363
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: mesa-stable@lists.freedesktop.org

diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c b/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
index 4404d8c..a820de7 100644 (file)
--- a/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
+++ b/src/gallium/drivers/nouveau/nvc0/nvc0_surface.c
@@ -1152,6 +1152,12 @@ nvc0_blit_3d(struct nvc0_context *nvc0, const struct pipe_blit_info *info)
                       NVC0_3D_VERTEX_ATTRIB_FORMAT_SIZE_32 |
                       NVC0_3D_VERTEX_ATTRIB_FORMAT_CONST);
    }
+   if (nvc0->state.instance_elts) {
+      nvc0->state.instance_elts = 0;
+      BEGIN_NVC0(push, NVC0_3D(MACRO_VERTEX_ARRAY_PER_INSTANCE), 2);
+      PUSH_DATA (push, n);
+      PUSH_DATA (push, 0);
+   }
    nvc0->state.num_vtxelts = 2;
 
    for (i = 0; i < info->dst.box.depth; ++i, z += dz) {