[PATCH v6 11/14] drm/mediatek: Support "None" alpha blending in Mixer

[CK Hu (胡俊光)]

Hi, Shawn:

On Fri, 2024-03-22 at 13:28 +0800, Shawn Sung wrote:
> From: Hsiao Chien Sung <shawn.sung at mediatek.com>
> 
> Support "None" blend mode on MediaTek's chips.
> 
> Please refer to the description of the commit
> "drm/mediatek: Support alpha blending in display driver"
> for more information.

But I would like you to describe the information in this patch instead
of referring to another patch. This patch could describe more detail,
and the integration patch could describe more brief.

Regards,
CK

> 
> Signed-off-by: Hsiao Chien Sung <shawn.sung at mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_ethdr.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c
> b/drivers/gpu/drm/mediatek/mtk_ethdr.c
> index 4b12ca285e84b..951e3e82a6a1a 100644
> --- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
> +++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
> @@ -178,7 +178,8 @@ void mtk_ethdr_layer_config(struct device *dev,
> unsigned int idx,
>  	if (state->base.pixel_blend_mode != DRM_MODE_BLEND_COVERAGE)
>  		mix_con |= PREMULTI_SOURCE;
>  
> -	if (state->base.fb && !state->base.fb->format->has_alpha) {
> +	if (state->base.pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE
> ||
> +	    (state->base.fb && !state->base.fb->format->has_alpha)) {
>  		/*
>  		 * Mixer doesn't support CONST_BLD mode,
>  		 * use a trick to make the output equivalent