dri3: Wait for all pending swapbuffers to be scheduled before touching the front

This implements a wait for glXWaitGL, glXCopySubBuffer, dri flush_front and
creation of fake front until all pending SwapBuffers have been committed to
hardware. Among other things this fixes piglit glx-copy-sub-buffers on dri3.

Signed-off-by: Thomas Hellstrom <[email protected]>
Reviewed-by: Brian Paul <[email protected]>
Reviewed-by: Sinclair Yeh <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>
Cc: <[email protected]>
(cherry picked from commit 185ef06fd2db782d9d3d6046580f7cece02c4797)

2 files changed, 21 insertions, 0 deletions

diff --git a/src/loader/loader_dri3_helper.c b/src/loader/loader_dri3_helper.c
index 1c93e7a96d3..c2ae8958120 100644
--- a/src/loader/loader_dri3_helper.c
+++ b/src/loader/loader_dri3_helper.c
@@ -504,6 +504,7 @@ loader_dri3_copy_sub_buffer(struct loader_dri3_drawable *draw,
                                      x, y, width, height, __BLIT_FLAG_FLUSH);
    }
 
+   loader_dri3_swapbuffer_barrier(draw);
    dri3_fence_reset(draw->conn, back);
    dri3_copy_area(draw->conn,
                   dri3_back_buffer(draw)->pixmap,
@@ -595,6 +596,7 @@ loader_dri3_wait_gl(struct loader_dri3_drawable *draw)
                                   front->height,
                                   0, 0, front->width,
                                   front->height, __BLIT_FLAG_FLUSH);
+   loader_dri3_swapbuffer_barrier(draw);
    loader_dri3_copy_drawable(draw, draw->drawable, front->pixmap);
 }
 
@@ -1258,6 +1260,7 @@ dri3_get_buffer(__DRIdrawable *driDrawable,
          }
          break;
       case loader_dri3_buffer_front:
+         loader_dri3_swapbuffer_barrier(draw);
          dri3_fence_reset(draw->conn, new_buffer);
          dri3_copy_area(draw->conn,
                         draw->drawable,
@@ -1431,3 +1434,18 @@ loader_dri3_update_drawable_geometry(struct loader_dri3_drawable *draw)
       free(geom_reply);
    }
 }
+
+
+/**
+ * Make sure the server has flushed all pending swap buffers to hardware
+ * for this drawable. Ideally we'd want to send an X protocol request to
+ * have the server block our connection until the swaps are complete. That
+ * would avoid the potential round-trip here.
+ */
+void
+loader_dri3_swapbuffer_barrier(struct loader_dri3_drawable *draw)
+{
+   int64_t ust, msc, sbc;
+
+   (void) loader_dri3_wait_for_sbc(draw, 0, &ust, &msc, &sbc);
+}
diff --git a/src/loader/loader_dri3_helper.h b/src/loader/loader_dri3_helper.h
index a865e463559..659b63afa7a 100644
--- a/src/loader/loader_dri3_helper.h
+++ b/src/loader/loader_dri3_helper.h
@@ -241,4 +241,7 @@ loader_dri3_get_buffers(__DRIdrawable *driDrawable,
 
 void
 loader_dri3_update_drawable_geometry(struct loader_dri3_drawable *draw);
+
+void
+loader_dri3_swapbuffer_barrier(struct loader_dri3_drawable *draw);
 #endif