[Mesa-dev] [PATCH] i965: Perform an explicit flush after doing _mesa_meta_pbo_TexSubImage

[Chris Wilson]

With the introduction of ARB_shader_image_load_store, shaders
are able to perform random memory accesses to texture that
are not easily tracked by the driver. Rather than see if this
texture is bound to an ImageUnit when we perform a TexImage command
via the GPU, and so its dirty state untracked by the normal implicit
flush mechanism, insert an explicit flush before the next access.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Jason Ekstrand <jason.ekstrand at intel.com>
Cc: Kenneth Graunke <kenneth at whitecape.org>
Cc: Neil Roberts <neil at linux.intel.com>
Cc: Francisco Jerez <currojerez at riseup.net>
---
 src/mesa/drivers/dri/i965/intel_tex_image.c    | 10 +++++++++-
 src/mesa/drivers/dri/i965/intel_tex_subimage.c | 10 +++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/intel_tex_image.c b/src/mesa/drivers/dri/i965/intel_tex_image.c
index 93a8cde..cdd4450 100644
--- a/src/mesa/drivers/dri/i965/intel_tex_image.c
+++ b/src/mesa/drivers/dri/i965/intel_tex_image.c
@@ -115,8 +115,16 @@ intelTexImage(struct gl_context * ctx,
                                    format, type, pixels,
                                    false /*allocate_storage*/,
                                    tex_busy, unpack);
-   if (ok)
+   if (ok) {
+      /* With the introduction of ARB_shader_image_load_store, shaders
+       * are able to perform random memory accesses to texture that
+       * are not easily tracked by the driver. Rather than see if this
+       * texture is bound to an ImageUnit and so its dirty state untracked
+       * insert an explicit flush before the next access.
+       */
+      brw_emit_mi_flush(brw_context(ctx));
       return;
+   }
 
    ok = intel_texsubimage_tiled_memcpy(ctx, dims, texImage,
                                        0, 0, 0, /*x,y,z offsets*/
diff --git a/src/mesa/drivers/dri/i965/intel_tex_subimage.c b/src/mesa/drivers/dri/i965/intel_tex_subimage.c
index 44921e5..aeb710a 100644
--- a/src/mesa/drivers/dri/i965/intel_tex_subimage.c
+++ b/src/mesa/drivers/dri/i965/intel_tex_subimage.c
@@ -218,8 +218,16 @@ intelTexSubImage(struct gl_context * ctx,
                                    xoffset, yoffset, zoffset,
                                    width, height, depth, format, type,
                                    pixels, false, tex_busy, packing);
-   if (ok)
+   if (ok) {
+      /* With the introduction of ARB_shader_image_load_store, shaders
+       * are able to perform random memory accesses to texture that
+       * are not easily tracked by the driver. Rather than see if this
+       * texture is bound to an ImageUnit and so its dirty state untracked
+       * insert an explicit flush before the next access.
+       */
+      brw_emit_mi_flush(brw_context(ctx));
       return;
+   }
 
    ok = intel_texsubimage_tiled_memcpy(ctx, dims, texImage,
                                        xoffset, yoffset, zoffset,
-- 
2.5.1