nvfx: new 2D: use a CPU copy for up to 4 pixels, up from 0

Seems a reasonable threshold for now.

Significantly speeds up Piglit's 1x1 glReadPixels (but, you know,
reading pixels in 1x1 blocks is NOT a good idea, especially if you
might be running on a less-than-perfect driver).

diff --git a/src/gallium/drivers/nvfx/nvfx_surface.c b/src/gallium/drivers/nvfx/nvfx_surface.c
index 8208c67..7efdd95 100644 (file)
--- a/src/gallium/drivers/nvfx/nvfx_surface.c
+++ b/src/gallium/drivers/nvfx/nvfx_surface.c
@@ -250,11 +250,7 @@ nvfx_resource_copy_region(struct pipe_context *pipe,
 
        static int copy_threshold = -1;
        if(copy_threshold < 0)
-       {
-               copy_threshold = debug_get_num_option("NOUVEAU_COPY_THRESHOLD", 0);
-               if(copy_threshold < 0)
-                       copy_threshold = 0;
-       }
+               copy_threshold = debug_get_num_option("NOUVEAU_COPY_THRESHOLD", 4);
 
        int dst_to_gpu = dstr->usage != PIPE_USAGE_DYNAMIC && dstr->usage != PIPE_USAGE_STAGING;
        int src_on_gpu = nvfx_resource_on_gpu(srcr);