On Wed, 2026-07-01 at 14:20 +0200, AngeloGioacchino Del Regno wrote:
> From: Paul-pl Chen <[email protected]>
> 
> For the new BLENDER component, the OVL ignore pixel alpha logic
> should be exported as a function and reused it.
> 
> Signed-off-by: Nancy Lin <[email protected]>
> Signed-off-by: Paul-pl Chen <[email protected]>
> Signed-off-by: AngeloGioacchino Del Regno 
> <[email protected]>
> ---
>  drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 68 +++++++++++++++++--------
>  drivers/gpu/drm/mediatek/mtk_disp_ovl.h |  8 +++
>  2 files changed, 56 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c 
> b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> index 9ded20202191..fa4607304acb 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> @@ -215,6 +215,23 @@ void mtk_ovl_disable_vblank(struct device *dev)
>       writel_relaxed(0x0, ovl->regs + DISP_REG_OVL_INTEN);
>  }
>  
> +bool mtk_ovl_is_ignore_pixel_alpha(struct mtk_plane_state *state, unsigned 
> int blend_mode)
> +{
> +     if (!state->base.fb)
> +             return false;
> +
> +     /*
> +      * Although the alpha channel can be ignored, CONST_BLD must be enabled
> +      * for XRGB format, otherwise OVL will still read the value from memory.
> +      * 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 (blend_mode == DRM_MODE_BLEND_PIXEL_NONE || 
> !state->base.fb->format->has_alpha)
> +             return true;
> +
> +     return false;
> +}
> +
>  u32 mtk_ovl_get_blend_modes(struct device *dev)
>  {
>       struct mtk_disp_ovl *ovl = dev_get_drvdata(dev);
> @@ -401,6 +418,29 @@ void mtk_ovl_layer_off(struct device *dev, unsigned int 
> idx,
>                     DISP_REG_OVL_RDMA_CTRL(idx));
>  }
>  
> +unsigned int mtk_ovl_get_blend_mode(struct mtk_plane_state *state, unsigned 
> int blend_modes)
> +{
> +     unsigned int blend_mode = DRM_MODE_BLEND_COVERAGE;
> +
> +     /*
> +      * For the platforms where OVL_CON_CLRFMT_MAN is defined in the 
> hardware data sheet
> +      * and supports premultiplied color formats, such as 
> OVL_CON_CLRFMT_PARGB888
> +      * and supports premultiplied color formats, such as 
> OVL_CON_CLRFMT_PARGB8888.
> +      *
> +      * Check blend_modes in the driver data to see if premultiplied mode is 
> supported.
> +      * If not, use coverage mode instead to set it to the supported color 
> formats.
> +      *
> +      * Current DRM assumption is that alpha is default premultiplied, so 
> the bitmask of
> +      * blend_modes must include BIT(DRM_MODE_BLEND_PREMULTI). Otherwise, 
> mtk_plane_init()
> +      * will get an error return from drm_plane_create_blend_mode_property() 
> and
> +      * state->base.pixel_blend_mode should not be used.
> +      */
> +     if (blend_modes & BIT(DRM_MODE_BLEND_PREMULTI))
> +             blend_mode = state->base.pixel_blend_mode;
> +
> +     return blend_mode;
> +}
> +
>  unsigned int mtk_ovl_fmt_convert(unsigned int fmt, unsigned int blend_mode,
>                                bool fmt_rgb565_is_0, bool color_convert,
>                                u8 clrfmt_shift, u32 clrfmt_man, u32 
> byte_swap, u32 rgb_swap)
> @@ -529,7 +569,7 @@ void mtk_ovl_layer_config(struct device *dev, unsigned 
> int idx,
>       unsigned int rotation = pending->rotation;
>       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 blend_mode = mtk_ovl_get_blend_mode(state, 
> ovl->data->blend_modes);

In [02/42], you add these statement.

+       if (ovl->data->blend_modes & BIT(DRM_MODE_BLEND_PREMULTI))
+                 con = mtk_ovl_fmt_convert(fmt, blend_mode,
+                                               ovl->data->fmt_rgb565_is_0, 
true, OVL_CON_CLRFMT_SHIFT,
+                                               OVL_CON_CLRFMT_MAN, 
OVL_CON_BYTE_SWAP, OVL_CON_RGB_SWAP);
+       else
+                 con = mtk_ovl_fmt_convert(fmt, DRM_MODE_BLEND_COVERAGE,
+                                               ovl->data->fmt_rgb565_is_0, 
true, OVL_CON_CLRFMT_SHIFT,
+                                               OVL_CON_CLRFMT_MAN, 
OVL_CON_BYTE_SWAP, OVL_CON_RGB_SWAP);

And here you change definition of blend_mode, so these statement could be 
simplified as

+       con = mtk_ovl_fmt_convert(fmt, blend_mode,
+                                 ovl->data->fmt_rgb565_is_0, true, 
OVL_CON_CLRFMT_SHIFT,
+                                 OVL_CON_CLRFMT_MAN, OVL_CON_BYTE_SWAP, 
OVL_CON_RGB_SWAP);


>       unsigned int ignore_pixel_alpha = 0;
>       unsigned int con;
>  
> @@ -554,17 +594,8 @@ void mtk_ovl_layer_config(struct device *dev, unsigned 
> int idx,
>                * For blend_modes supported SoCs, always enable alpha blending.
>                * For blend_modes unsupported SoCs, enable alpha blending when 
> has_alpha is set.
>                */
> -             if (blend_mode || state->base.fb->format->has_alpha)
> +             if (state->base.pixel_blend_mode || 
> state->base.fb->format->has_alpha)
>                       con |= OVL_CON_AEN;
> -
> -             /*
> -              * Although the alpha channel can be ignored, CONST_BLD must be 
> enabled
> -              * for XRGB format, otherwise OVL will still read the value 
> from memory.
> -              * 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 (blend_mode == DRM_MODE_BLEND_PIXEL_NONE || 
> !state->base.fb->format->has_alpha)
> -                     ignore_pixel_alpha = OVL_CONST_BLEND;
>       }
>  
>       /*
> @@ -590,6 +621,9 @@ void mtk_ovl_layer_config(struct device *dev, unsigned 
> int idx,
>  
>       mtk_ddp_write_relaxed(cmdq_pkt, con, &ovl->cmdq_reg, ovl->regs,
>                             DISP_REG_OVL_CON(idx));
> +
> +     if (mtk_ovl_is_ignore_pixel_alpha(state, blend_mode))

if (mtk_ovl_is_ignore_pixel_alpha(state, state->base.pixel_blend_mode))

Regards,
CK

> +             ignore_pixel_alpha = OVL_CONST_BLEND;
>       mtk_ddp_write_relaxed(cmdq_pkt, pitch_lsb | ignore_pixel_alpha,
>                             &ovl->cmdq_reg, ovl->regs, 
> DISP_REG_OVL_PITCH(idx));
>       mtk_ddp_write_relaxed(cmdq_pkt, src_size, &ovl->cmdq_reg, ovl->regs,
> 

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