Re: [PATCH] drm/mediatek: Add support for 180-degree rotation in the display driver

["CK Hu (胡俊光)" <ck.hu@mediatek.com>]

Hi, Jason:

On Mon, 2024-11-18 at 10:51 +0800, Jason-JH.Lin wrote:
> mediatek-drm driver reported the capability of 180-degree rotation by
> adding `DRM_MODE_ROTATE_180` to the plane property, as flip-x combined
> with flip-y equals a 180-degree rotation. However, we did not handle
> the rotation property in the driver and lead to rotation issues.

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Fixes: 74608d8feefd ("drm/mediatek: Add DRM_MODE_ROTATE_0 to rotation property")
> Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> index e0c0bb01f65a..cc825c4f2e09 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> @@ -472,6 +472,7 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
>  	unsigned int hdr_pitch = pending->hdr_pitch;
>  	unsigned int fmt = pending->format;
>  	unsigned int offset = (pending->y << 16) | pending->x;
> +	unsigned int rotation = pending->rotation;
>  	unsigned int src_size = (pending->height << 16) | pending->width;
>  	unsigned int blend_mode = state->base.pixel_blend_mode;
>  	unsigned int ignore_pixel_alpha = 0;
> @@ -513,12 +514,19 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
>  			ignore_pixel_alpha = OVL_CONST_BLEND;
>  	}
>  
> -	if (pending->rotation & DRM_MODE_REFLECT_Y) {
> +	/*
> +	 * Treat rotate 180 as flip x + flip y, and XOR the original rotation value
> +	 * to flip x + flip y to support both in the same time.
> +	 */
> +	if (rotation & DRM_MODE_ROTATE_180)
> +		rotation ^= DRM_MODE_REFLECT_X | DRM_MODE_REFLECT_Y;
> +
> +	if (rotation & DRM_MODE_REFLECT_Y) {
>  		con |= OVL_CON_VIRT_FLIP;
>  		addr += (pending->height - 1) * pending->pitch;
>  	}
>  
> -	if (pending->rotation & DRM_MODE_REFLECT_X) {
> +	if (rotation & DRM_MODE_REFLECT_X) {
>  		con |= OVL_CON_HORZ_FLIP;
>  		addr += pending->pitch - 1;
>  	}