[Mesa-dev] [PATCH] i965: Fix fast depth clears for surfaces with a dimension of 16384.

[Anuj Phogat]

On Tue, Jan 24, 2017 at 3:32 PM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> I hadn't bothered to set this bit because I figured it would just
> paper over us getting the rectangle wrong.  But it turns out that
> there is a legitimate reason to use it, so let's do so.
>
> The alternative would be to chop up 16k clears to multiple 8k clears,
> which is pointlessly painful.
>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> ---
>  src/mesa/drivers/dri/i965/gen8_depth_state.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/src/mesa/drivers/dri/i965/gen8_depth_state.c b/src/mesa/drivers/dri/i965/gen8_depth_state.c
> index ec296698267..de5a16e91bf 100644
> --- a/src/mesa/drivers/dri/i965/gen8_depth_state.c
> +++ b/src/mesa/drivers/dri/i965/gen8_depth_state.c
> @@ -477,6 +477,17 @@ gen8_hiz_exec(struct brw_context *brw, struct intel_mipmap_tree *mt,
>        break;
>     case BLORP_HIZ_OP_DEPTH_CLEAR:
>        dw1 |= GEN8_WM_HZ_DEPTH_CLEAR;
> +
> +      /* The "Clear Rectangle X Max" (and Y Max) fields are exclusive,
> +       * rather than inclusive, and limited to 16383.  This means that
> +       * for a 16384x16384 render target, we would miss the last pixel.
> +       *
> +       * To work around this, we have to set the "Full Surface Depth
> +       * and Stencil Clear" bit.  We can do this in all cases because
> +       * we always clear the full rectangle anyway.  We'll need to
> +       * change this if we ever add scissored clear support.
> +       */
> +      dw1 |= GEN8_WM_HZ_FULL_SURFACE_DEPTH_CLEAR;
>        break;
>     case BLORP_HIZ_OP_NONE:
>        unreachable("Should not get here.");
> --
> 2.11.0
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev

Verified the restriction from PRM. Patch looks good to me.
Reviewed-by: Anuj Phogat <anuj.phogat at gmail.com>