[Mesa-dev] [PATCH] i965: Prefer Meta over the BLT for BlitFramebuffer.

[Kenneth Graunke]

There's some debate about whether we should use Meta or BLORP,
but either should run circles around the BLT engine.

In particular, this means that Gen8+ will use the 3D engine for blits,
like we do on Gen6-7.

Improves performance in "copypixrate -blit -back" (from Mesa demos)
by 232.037% +/- 3.15795% (n=10) on Broadwell GT3e.

v2: Rebase on Laura's changes.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
Cc: "10.5" <mesa-stable at lists.freedesktop.org>
---
 src/mesa/drivers/dri/i965/intel_fbo.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/intel_fbo.c b/src/mesa/drivers/dri/i965/intel_fbo.c
index 3ee1a55..174cea0 100644
--- a/src/mesa/drivers/dri/i965/intel_fbo.c
+++ b/src/mesa/drivers/dri/i965/intel_fbo.c
@@ -873,54 +873,54 @@ intel_blit_framebuffer(struct gl_context *ctx,
 
    /* Page 679 of OpenGL 4.4 spec says:
     *    "Added BlitFramebuffer to commands affected by conditional rendering in
     *     section 10.10 (Bug 9562)."
     */
    if (!_mesa_check_conditional_render(ctx))
       return;
 
    mask = brw_blorp_framebuffer(brw, readFb, drawFb,
                                 srcX0, srcY0, srcX1, srcY1,
                                 dstX0, dstY0, dstX1, dstY1,
                                 mask, filter);
    if (mask == 0x0)
       return;
 
+   mask = _mesa_meta_BlitFramebuffer(ctx, readFb, drawFb,
+                                     srcX0, srcY0, srcX1, srcY1,
+                                     dstX0, dstY0, dstX1, dstY1,
+                                     mask, filter);
+   if (mask == 0x0)
+      return;
+
    if (brw->gen >= 8 && (mask & GL_STENCIL_BUFFER_BIT)) {
       brw_meta_fbo_stencil_blit(brw_context(ctx), readFb, drawFb,
                                 srcX0, srcY0, srcX1, srcY1,
                                 dstX0, dstY0, dstX1, dstY1);
       mask &= ~GL_STENCIL_BUFFER_BIT;
       if (mask == 0x0)
          return;
    }
 
    /* Try using the BLT engine. */
    mask = intel_blit_framebuffer_with_blitter(ctx, readFb, drawFb,
                                               srcX0, srcY0, srcX1, srcY1,
                                               dstX0, dstY0, dstX1, dstY1,
                                               mask, filter);
    if (mask == 0x0)
       return;
 
-   mask = _mesa_meta_BlitFramebuffer(ctx, readFb, drawFb,
-                                     srcX0, srcY0, srcX1, srcY1,
-                                     dstX0, dstY0, dstX1, dstY1,
-                                     mask, filter);
-   if (mask == 0x0)
-      return;
-
    _swrast_BlitFramebuffer(ctx, readFb, drawFb,
                            srcX0, srcY0, srcX1, srcY1,
                            dstX0, dstY0, dstX1, dstY1,
                            mask, filter);
 }
 
 /**
  * Does the renderbuffer have hiz enabled?
  */
 bool
 intel_renderbuffer_has_hiz(struct intel_renderbuffer *irb)
 {
    return intel_miptree_level_has_hiz(irb->mt, irb->mt_level);
 }
 
-- 
2.2.2