[Nouveau] [PATCH v2 2/4] drm/vc4: Take underscan setup into account when updating planes

[Ville Syrjälä]

On Fri, May 11, 2018 at 04:59:17PM +0200, Boris Brezillon wrote:
> Applying an underscan setup is just a matter of scaling all planes
> appropriately and adjusting the CRTC X/Y offset to account for the
> horizontal and vertical border.
> 
> Create an vc4_plane_underscan_adj() function doing that and call it from
> vc4_plane_setup_clipping_and_scaling() so that we are ready to attach
> underscan properties to the HDMI connector.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon at bootlin.com>
> ---
> Changes in v2:
> - Take changes on hborder/vborder meaning into account
> ---
>  drivers/gpu/drm/vc4/vc4_plane.c | 49 ++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 48 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c
> index 71d44c357d35..61ed60841cd6 100644
> --- a/drivers/gpu/drm/vc4/vc4_plane.c
> +++ b/drivers/gpu/drm/vc4/vc4_plane.c
> @@ -258,6 +258,49 @@ static u32 vc4_get_scl_field(struct drm_plane_state *state, int plane)
>  	}
>  }
>  
> +static int vc4_plane_underscan_adj(struct drm_plane_state *pstate)
> +{
> +	struct vc4_plane_state *vc4_pstate = to_vc4_plane_state(pstate);
> +	struct drm_connector_state *conn_state = NULL;
> +	struct drm_connector *conn;
> +	struct drm_crtc_state *crtc_state;
> +	int i;
> +
> +	for_each_new_connector_in_state(pstate->state, conn, conn_state, i) {
> +		if (conn_state->crtc == pstate->crtc)
> +			break;
> +	}
> +
> +	if (i == pstate->state->num_connector)
> +		return 0;
> +
> +	if (conn_state->underscan.mode != DRM_UNDERSCAN_ON)
> +		return 0;
> +
> +	crtc_state = drm_atomic_get_new_crtc_state(pstate->state,
> +						   pstate->crtc);
> +
> +	if (conn_state->underscan.hborder >= crtc_state->mode.hdisplay ||
> +	    conn_state->underscan.vborder >= crtc_state->mode.vdisplay)
> +		return -EINVAL;

border * 2 ?

> +
> +	vc4_pstate->crtc_x += conn_state->underscan.hborder;
> +	vc4_pstate->crtc_y += conn_state->underscan.vborder;
> +	vc4_pstate->crtc_w = (vc4_pstate->crtc_w *
> +			      (crtc_state->mode.hdisplay -
> +			       (conn_state->underscan.hborder * 2))) /
> +			     crtc_state->mode.hdisplay;
> +	vc4_pstate->crtc_h = (vc4_pstate->crtc_h *
> +			      (crtc_state->mode.vdisplay -
> +			       (conn_state->underscan.vborder * 2))) /
> +			     crtc_state->mode.vdisplay;

So you're now scaling all planes? The code seems to reject scaling for
the cursor plane, how are you dealing with that? Or just no cursor
allowed when underscanning?

I'm also wondering if there's any way we can reconcile these border
props with the scaling mode prop, should we ever wish to expose
these props on connectors that already have the scaling mode prop.
Maybe we just have to require the scaling mode to be set to fullscreen 
to allow borders to be specified explictly?

> +
> +	if (!vc4_pstate->crtc_w || !vc4_pstate->crtc_h)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>  static int vc4_plane_setup_clipping_and_scaling(struct drm_plane_state *state)
>  {
>  	struct drm_plane *plane = state->plane;
> @@ -269,7 +312,7 @@ static int vc4_plane_setup_clipping_and_scaling(struct drm_plane_state *state)
>  	int num_planes = fb->format->num_planes;
>  	u32 h_subsample = 1;
>  	u32 v_subsample = 1;
> -	int i;
> +	int i, ret;
>  
>  	for (i = 0; i < num_planes; i++)
>  		vc4_state->offsets[i] = bo->paddr + fb->offsets[i];
> @@ -292,6 +335,10 @@ static int vc4_plane_setup_clipping_and_scaling(struct drm_plane_state *state)
>  	vc4_state->crtc_w = state->crtc_w;
>  	vc4_state->crtc_h = state->crtc_h;
>  
> +	ret = vc4_plane_underscan_adj(state);
> +	if (ret)
> +		return ret;
> +
>  	vc4_state->x_scaling[0] = vc4_get_scaling_mode(vc4_state->src_w[0],
>  						       vc4_state->crtc_w);
>  	vc4_state->y_scaling[0] = vc4_get_scaling_mode(vc4_state->src_h[0],
> -- 
> 2.14.1
> 
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-- 
Ville Syrjälä
Intel