[Mesa-dev] [v4 02/11] i965: Relax assertion of halign == 16 for lossless compressed aux

[Ben Widawsky]

On Thu, Apr 21, 2016 at 02:58:57PM +0300, Topi Pohjolainen wrote:
> Signed-off-by: Topi Pohjolainen <topi.pohjolainen at intel.com>
> ---
>  src/mesa/drivers/dri/i965/intel_mipmap_tree.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> index ae08300..b68575f 100644
> --- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> +++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> @@ -556,8 +556,13 @@ intel_miptree_create_layout(struct brw_context *brw,
>     } else if (brw->gen >= 9 && num_samples > 1) {
>        layout_flags |= MIPTREE_LAYOUT_FORCE_HALIGN16;
>     } else {
> +      const bool is_lossless_compressed_aux =
> +         brw->gen >= 9 && num_samples == 1 &&
> +         mt->format == MESA_FORMAT_R_UINT32;
> +
>        /* For now, nothing else has this requirement */
> -      assert((layout_flags & MIPTREE_LAYOUT_FORCE_HALIGN16) == 0);
> +      assert(is_lossless_compressed_aux ||
> +             (layout_flags & MIPTREE_LAYOUT_FORCE_HALIGN16) == 0);
>     }
>  
>     brw_miptree_layout(brw, mt, layout_flags);

I'd just drop the else condition entirely instead. The else case assertion also
becomes invalid when we want to fast clear multi LOD and arrayed surfaces. I'm
slightly worried that the assertion is somewhat frail and not future proof.

Also the format check makes me wonder if you want to add some assertion or
condition to intel_miptree_is_lossless_compressed? ie.

diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
index 17c87a2..467a60b 100644
--- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
+++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
@@ -296,6 +296,9 @@ intel_miptree_is_lossless_compressed(const struct brw_context *brw,
    if (mt->msaa_layout != INTEL_MSAA_LAYOUT_CMS)
       return false;
 
+   if (mt->format == MESA_FORMAT_R_UINT32)
+      return false;
+
    /* And finally distinguish between msaa and single sample case. */
    return mt->num_samples <= 1;
 }

Either way:
Reviewed-by: Ben Widawsky <ben at bwidawsk.net>