gallium: fix some surface usage bugs

When a surface is created with GPU_WRITE that really means "GPU render"
and that can involve reads (blending).  Set surface usage to
PIPE_BUFFER_USAGE_CPU_READ + WRITE.  Fixes progs/demos/lodbias demo.

Also, mark texture as 'modified' when mapped for writing so that the tile
cache can know when to freshen a cached tile.  Fixes glTexSubImage2D().

1 files changed, 2 insertions, 0 deletions

diff --git a/src/gallium/drivers/softpipe/sp_texture.h b/src/gallium/drivers/softpipe/sp_texture.h
index 779a9d8fc97..0e1017632c9 100644
--- a/src/gallium/drivers/softpipe/sp_texture.h
+++ b/src/gallium/drivers/softpipe/sp_texture.h
@@ -47,6 +47,8 @@ struct softpipe_texture
    /* The data is held here:
     */
    struct pipe_buffer *buffer;
+
+   boolean modified;
 };