[PATCH v2] drm/rockchip: Disable blending for win0

[Sean Paul]

On Wed, Apr 18, 2018 at 10:31:52AM -0700, Kristian H. Kristensen wrote:
> Blending win0 with the background color doesn't seem to work
> correctly. 

Did you come to a conclusion about whether this applies across all Rk vops, or
just 3399 big?

Sean

> We only get the background color, no matter the contents of
> the win0 framebuffer.  However, blending pre-multiplied color with the
> default opaque black default background color is a no-op, so we can
> just disable blending to get the correct result.
> 
> Signed-off-by: Kristian H. Kristensen <hoegsberg at chromium.org>
> Cc: Sandy Huang <hjc at rock-chips.com>
> Cc: Sean Paul <seanpaul at chromium.org>
> ---
> 
> v2: Drop CHROMIUM: prefix, rebase on Linus' master
> 
>  drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> index 53d4afe15278..753a7548da84 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
> @@ -76,6 +76,9 @@
>  #define VOP_WIN_GET_YRGBADDR(vop, win) \
>  		vop_readl(vop, win->base + win->phy->yrgb_mst.offset)
>  
> +#define VOP_WIN_TO_INDEX(vop_win) \
> +	((vop_win) - (vop_win)->vop->win)
> +
>  #define to_vop(x) container_of(x, struct vop, crtc)
>  #define to_vop_win(x) container_of(x, struct vop_win, base)
>  
> @@ -708,6 +711,7 @@ static void vop_plane_atomic_update(struct drm_plane *plane,
>  	dma_addr_t dma_addr;
>  	uint32_t val;
>  	bool rb_swap;
> +	int win_index = VOP_WIN_TO_INDEX(vop_win);
>  	int format;
>  
>  	/*
> @@ -777,7 +781,14 @@ static void vop_plane_atomic_update(struct drm_plane *plane,
>  	rb_swap = has_rb_swapped(fb->format->format);
>  	VOP_WIN_SET(vop, win, rb_swap, rb_swap);
>  
> -	if (fb->format->has_alpha) {
> +	/*
> +	 * Blending win0 with the background color doesn't seem to work
> +	 * correctly. We only get the background color, no matter the contents
> +	 * of the win0 framebuffer.  However, blending pre-multiplied color
> +	 * with the default opaque black default background color is a no-op,
> +	 * so we can just disable blending to get the correct result.
> +	 */
> +	if (fb->format->has_alpha && win_index > 0) {
>  		VOP_WIN_SET(vop, win, dst_alpha_ctl,
>  			    DST_FACTOR_M0(ALPHA_SRC_INVERSE));
>  		val = SRC_ALPHA_EN(1) | SRC_COLOR_M0(ALPHA_SRC_PRE_MUL) |
> -- 
> 2.17.0.484.g0c8726318c-goog
> 

-- 
Sean Paul, Software Engineer, Google / Chromium OS