[Mesa-dev] [PATCH] i965/miptree: Initialize mcs buffer only until clear color

[Rafael Antognolli]

On Fri, Apr 06, 2018 at 06:07:52PM +0300, Topi Pohjolainen wrote:
> Otherwise even the clear color gets initialised to 0xFF. This
> allows enabling of color fast clears on ICL without regressing
> multisampling tests.
> 
> CC: Rafael Antognolli <rafael.antognolli at intel.com>
> CC: Jason Ekstrand <jason at jlekstrand.net>
> CC: Nanley Chery <nanley.g.chery at intel.com>
> 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 89074a6..25f901d 100644
> --- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> +++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> @@ -1680,7 +1680,12 @@ intel_miptree_init_mcs(struct brw_context *brw,
>        return;
>     }
>     void *data = map;
> -   memset(data, init_value, mt->mcs_buf->size);
> +
> +   /* Only initialize until clear color (if present). */
> +   const unsigned aux_size = mt->mcs_buf->clear_color_offset ?
> +                                mt->mcs_buf->clear_color_offset :
> +                                mt->mcs_buf->size;
> +   memset(data, init_value, aux_size);

Hmm... that's a good catch, and I think we definitely should not
overwrite the clear color here.

However, the initial value of the clear color shouldn't matter, right? I
think there might still be a bug hidden somewhere...

Regardless of that, this patch is

Reviewed-by: Rafael Antognolli <rafael.antognolli at intel.com>

>     brw_bo_unmap(mt->mcs_buf->bo);
>  }
>  
> -- 
> 2.7.4
>