[Mesa-dev] [PATCH 3/3] i965: Use Y-tiled blits to untile for cached mappings of miptrees.

[Kenneth Graunke]

On 05/06/2013 04:41 PM, Eric Anholt wrote:
> Fixes a regression in firefox's ReadScreenIntoImageSurface ->
> glReadPixels() path with the introduction of Y tiling.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=64213
> ---
>   src/mesa/drivers/dri/intel/intel_mipmap_tree.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
> index 8970228..7f4cb4a 100644
> --- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
> +++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
> @@ -1903,7 +1903,8 @@ intel_miptree_map_singlesample(struct intel_context *intel,
>      else if (intel->has_llc &&
>               !(mode & GL_MAP_WRITE_BIT) &&
>               !mt->compressed &&
> -            mt->region->tiling == I915_TILING_X &&
> +            (mt->region->tiling == I915_TILING_X ||
> +             (intel->gen >= 6 && mt->region->tiling == I915_TILING_Y)) &&
>               mt->region->pitch < 32768) {
>         intel_miptree_map_blit(intel, mt, map, level, slice);
>      } else if (mt->region->tiling != I915_TILING_NONE &&

This patch is fine, but the blitter can handle untiled buffers as well. 
It might be even better (and simpler) as:

(intel->gen >= 6 || mt->region->Tiling != I915_TILING_Y)

That said, untiled buffers can also be mapped via the CPU rather than 
the GTT with a fence, so maybe it's not as big of a deal.

Either way, this series is:
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>