[Mesa-dev] [PATCH 1/2] dri: add backbuffer use flag

[Marek Olšák]

From: Axel Davy <axel.davy at ens.fr>

This will be used by the next commit.
---
 include/GL/internal/dri_interface.h     | 5 +++++
 src/egl/drivers/dri2/platform_wayland.c | 8 +++++---
 src/loader/loader_dri3_helper.c         | 6 ++++--
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/include/GL/internal/dri_interface.h b/include/GL/internal/dri_interface.h
index 6bbd3fa..2b49a29 100644
--- a/include/GL/internal/dri_interface.h
+++ b/include/GL/internal/dri_interface.h
@@ -1100,6 +1100,11 @@ struct __DRIdri2ExtensionRec {
 #define __DRI_IMAGE_USE_SCANOUT		0x0002
 #define __DRI_IMAGE_USE_CURSOR		0x0004 /* Depricated */
 #define __DRI_IMAGE_USE_LINEAR		0x0008
+/* The buffer will only be read by an external process after SwapBuffers,
+ * in contrary to gbm buffers, front buffers and fake front buffers, which
+ * could be read after a flush."
+ */
+#define __DRI_IMAGE_USE_BACKBUFFER      0x0010
 
 
 /**
diff --git a/src/egl/drivers/dri2/platform_wayland.c b/src/egl/drivers/dri2/platform_wayland.c
index 341acb7..ff0d5c8 100644
--- a/src/egl/drivers/dri2/platform_wayland.c
+++ b/src/egl/drivers/dri2/platform_wayland.c
@@ -305,7 +305,7 @@ get_back_bo(struct dri2_egl_surface *dri2_surf)
 {
    struct dri2_egl_display *dri2_dpy =
       dri2_egl_display(dri2_surf->base.Resource.Display);
-   int i;
+   int i, use_flags;
    unsigned int dri_image_format;
 
    /* currently supports three WL DRM formats,
@@ -352,6 +352,8 @@ get_back_bo(struct dri2_egl_surface *dri2_surf)
    if (dri2_surf->back == NULL)
       return -1;
 
+   use_flags = __DRI_IMAGE_USE_SHARE | __DRI_IMAGE_USE_BACKBUFFER;
+
    if (dri2_dpy->is_different_gpu &&
        dri2_surf->back->linear_copy == NULL) {
        dri2_surf->back->linear_copy =
@@ -359,7 +361,7 @@ get_back_bo(struct dri2_egl_surface *dri2_surf)
                                       dri2_surf->base.Width,
                                       dri2_surf->base.Height,
                                       dri_image_format,
-                                      __DRI_IMAGE_USE_SHARE |
+                                      use_flags |
                                       __DRI_IMAGE_USE_LINEAR,
                                       NULL);
       if (dri2_surf->back->linear_copy == NULL)
@@ -373,7 +375,7 @@ get_back_bo(struct dri2_egl_surface *dri2_surf)
                                       dri2_surf->base.Height,
                                       dri_image_format,
                                       dri2_dpy->is_different_gpu ?
-                                         0 : __DRI_IMAGE_USE_SHARE,
+                                         0 : use_flags,
                                       NULL);
       dri2_surf->back->age = 0;
    }
diff --git a/src/loader/loader_dri3_helper.c b/src/loader/loader_dri3_helper.c
index 62bfe84..896f225 100644
--- a/src/loader/loader_dri3_helper.c
+++ b/src/loader/loader_dri3_helper.c
@@ -858,7 +858,8 @@ dri3_alloc_render_buffer(struct loader_dri3_drawable *draw, unsigned int format,
                                                       width, height,
                                                       format,
                                                       __DRI_IMAGE_USE_SHARE |
-                                                      __DRI_IMAGE_USE_SCANOUT,
+                                                      __DRI_IMAGE_USE_SCANOUT |
+                                                      __DRI_IMAGE_USE_BACKBUFFER,
                                                       buffer);
       pixmap_buffer = buffer->image;
 
@@ -878,7 +879,8 @@ dri3_alloc_render_buffer(struct loader_dri3_drawable *draw, unsigned int format,
         (draw->ext->image->createImage)(draw->dri_screen,
                                         width, height, format,
                                         __DRI_IMAGE_USE_SHARE |
-                                           __DRI_IMAGE_USE_LINEAR,
+                                        __DRI_IMAGE_USE_LINEAR |
+                                        __DRI_IMAGE_USE_BACKBUFFER,
                                         buffer);
       pixmap_buffer = buffer->linear_buffer;
 
-- 
2.5.0