[Mesa-dev] [PATCH 2/2] nouveau: always enable at least one RC

[Ilia Mirkin]

On Sat, Aug 27, 2016 at 8:01 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> Experimentally, this is required for glxgears and others to display the
> proper colors.
>
> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
> ---
>  src/mesa/drivers/dri/nouveau/nv20_state_frag.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/mesa/drivers/dri/nouveau/nv20_state_frag.c b/src/mesa/drivers/dri/nouveau/nv20_state_frag.c
> index 492ecdc..2c5c2db 100644
> --- a/src/mesa/drivers/dri/nouveau/nv20_state_frag.c
> +++ b/src/mesa/drivers/dri/nouveau/nv20_state_frag.c
> @@ -67,5 +67,5 @@ nv20_emit_frag(struct gl_context *ctx, int emit)
>         PUSH_DATA (push, in >> 32);
>
>         BEGIN_NV04(push, NV20_3D(RC_ENABLE), 1);
> -       PUSH_DATA (push, n);
> +       PUSH_DATA (push, MAX2(1, n));

As an add-on analysis, it looks like that's what this driver did back
in antiquity:

https://cgit.freedesktop.org/mesa/mesa/tree/src/mesa/drivers/dri/nouveau/nv10_state_frag.c?h=7.10#n365
*n = log2i(ctx->Texture._EnabledUnits) + 1;

Whereas now it does

https://cgit.freedesktop.org/mesa/mesa/tree/src/mesa/drivers/dri/nouveau/nv10_state_frag.c?h=12.0#n365
*n = ctx->Texture._MaxEnabledTexImageUnit + 1;

The old code would always return at least 1, while the new code will
return 0 when there are no enabled tex image units.

  -ilia

>  }
> --
> 2.7.3
>