drm/mediatek: Fix XRGB setting error in Mixer

Although the alpha channel in XRGB formats can be ignored, ALPHA_CON
must be configured accordingly when using XRGB formats or it will still
affects CRC generation.

Fixes: d886c0009bd0 ("drm/mediatek: Add ETHDR support for MT8195")
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20240620-igt-v3-4-a9d62d2e2c7e@mediatek.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c b/drivers/gpu/drm/mediatek/mtk_ethdr.c
index d7d16482c9473148573dd4f16da4a78d82fdf35f..5c52e514ae301d8d2aea3533cc2dd4d65ddfefe8 100644 (file)
--- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
+++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
@@ -153,6 +153,7 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
        unsigned int offset = (pending->x & 1) << 31 | pending->y << 16 | pending->x;
        unsigned int align_width = ALIGN_DOWN(pending->width, 2);
        unsigned int alpha_con = 0;
+       bool replace_src_a = false;
 
        dev_dbg(dev, "%s+ idx:%d", __func__, idx);
 
@@ -167,7 +168,15 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
        if (state->base.fb && state->base.fb->format->has_alpha)
                alpha_con = MIXER_ALPHA_AEN | MIXER_ALPHA;
 
-       mtk_mmsys_mixer_in_config(priv->mmsys_dev, idx + 1, alpha_con ? false : true,
+       if (state->base.fb && !state->base.fb->format->has_alpha) {
+               /*
+                * Mixer doesn't support CONST_BLD mode,
+                * use a trick to make the output equivalent
+                */
+               replace_src_a = true;
+       }
+
+       mtk_mmsys_mixer_in_config(priv->mmsys_dev, idx + 1, replace_src_a,
                                  MIXER_ALPHA,
                                  pending->x & 1 ? MIXER_INX_MODE_EVEN_EXTEND :
                                  MIXER_INX_MODE_BYPASS, align_width / 2 - 1, cmdq_pkt);