[Mesa-dev] [PATCH] i965/cnl: Avoid fast-clearing sRGB render buffers

[Nanley Chery]

On Fri, Dec 01, 2017 at 02:44:42PM -0800, Nanley Chery wrote:
> Gen10 doesn't automatically decode the clear color of sRGB buffers. To
> get correct rendering, avoid fast-clearing such buffers for now.
> 
> The driver now passes the following piglit tests:
> * spec at arb_framebuffer_srgb@msaa-fast-clear
> * spec at ext_texture_srgb@multisample-fast-clear gl_ext_texture_srgb
> 
> Suggested-by: Kenneth Graunke <kenneth at whitecape.org>
> Suggested-by: Jason Ekstrand <jason at jlekstrand.net>
> Signed-off-by: Nanley Chery <nanley.g.chery at intel.com>
> ---
> 
> This patch is currently going through the jenkins pipeline.
> 

The run came back green.

-Nanley

>  src/mesa/drivers/dri/i965/brw_meta_util.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_meta_util.c b/src/mesa/drivers/dri/i965/brw_meta_util.c
> index ba92168934..54dc6a5ff9 100644
> --- a/src/mesa/drivers/dri/i965/brw_meta_util.c
> +++ b/src/mesa/drivers/dri/i965/brw_meta_util.c
> @@ -298,13 +298,23 @@ brw_is_color_fast_clear_compatible(struct brw_context *brw,
>      * resolved in intel_update_state. In that case it's pointless to do a
>      * fast clear because it's very likely to be immediately resolved.
>      */
> +   const bool srgb_rb = _mesa_get_srgb_format_linear(mt->format) != mt->format;
>     if (devinfo->gen >= 9 &&
>         mt->surf.samples == 1 &&
> -       ctx->Color.sRGBEnabled &&
> -       _mesa_get_srgb_format_linear(mt->format) != mt->format)
> +       ctx->Color.sRGBEnabled && srgb_rb)
>        return false;
>  
> +  /* Gen10 doesn't automatically decode the clear color of sRGB buffers. Since
> +   * we currently don't perform this decode in software, avoid a fast-clear
> +   * altogether. TODO: Do this in software.
> +   */
>     const mesa_format format = _mesa_get_render_format(ctx, mt->format);
> +   if (devinfo->gen >= 10 && srgb_rb) {
> +      perf_debug("sRGB fast clear not enabled for (%s)",
> +                 _mesa_get_format_name(format));
> +      return false;
> +   }
> +
>     if (_mesa_is_format_integer_color(format)) {
>        if (devinfo->gen >= 8) {
>           perf_debug("Integer fast clear not enabled for (%s)",
> -- 
> 2.15.1
>