[PATCH v9 15/21] drm/mediatek: Support "None" blending in Mixer

[CK Hu (胡俊光)]

Hi, Shawn:

On Fri, 2024-06-14 at 10:46 +0800, Shawn Sung wrote:
> From: Hsiao Chien Sung <shawn.sung at mediatek.com>
> 
> Support "None" alpha blending mode on MediaTek's chips.

Reviewed-by: CK Hu <ck.hu at mediatek.com>

> 
> Signed-off-by: Hsiao Chien Sung <shawn.sung at mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_ethdr.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c b/drivers/gpu/drm/mediatek/mtk_ethdr.c
> index 7eaafd44f320..907c0ed34c64 100644
> --- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
> +++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
> @@ -3,6 +3,7 @@
>   * Copyright (c) 2021 MediaTek Inc.
>   */
>  
> +#include <drm/drm_blend.h>
>  #include <drm/drm_fourcc.h>
>  #include <drm/drm_framebuffer.h>
>  #include <linux/clk.h>
> @@ -175,7 +176,8 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
>  		alpha_con |= state->base.alpha & MIXER_ALPHA;
>  	}
>  
> -	if (state->base.fb && !state->base.fb->format->has_alpha) {
> +	if ((state->base.fb && !state->base.fb->format->has_alpha) ||
> +	    state->base.pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE) {
>  		/*
>  		 * Mixer doesn't support CONST_BLD mode,
>  		 * use a trick to make the output equivalent