drm/mediatek: Support "None" blending in OVL

Support "None" alpha blending mode on MediaTek's chips.

Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20240717-alpha-blending-v4-1-4b1c806c0749@mediatek.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
index 9d6d9fd8342e413c839a8948efabbf9ae27e2ca8..add671c38613c095069fea822b2e20375980ab70 100644 (file)
--- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
@@ -434,6 +434,7 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
        unsigned int fmt = pending->format;
        unsigned int offset = (pending->y << 16) | pending->x;
        unsigned int src_size = (pending->height << 16) | pending->width;
+       unsigned int blend_mode = state->base.pixel_blend_mode;
        unsigned int ignore_pixel_alpha = 0;
        unsigned int con;
        bool is_afbc = pending->modifier != DRM_FORMAT_MOD_LINEAR;
@@ -463,7 +464,8 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
         * For RGB888 related formats, whether CONST_BLD is enabled or not won't
         * affect the result. Therefore we use !has_alpha as the condition.
         */
-       if (state->base.fb && !state->base.fb->format->has_alpha)
+       if ((state->base.fb && !state->base.fb->format->has_alpha) ||
+           blend_mode == DRM_MODE_BLEND_PIXEL_NONE)
                ignore_pixel_alpha = OVL_CONST_BLEND;
 
        if (pending->rotation & DRM_MODE_REFLECT_Y) {