[PATCH v18 3/4] compositor-drm: Add modes to drm_output_propose_state

Pekka Paalanen ppaalanen at gmail.com
Tue Jul 10 14:35:23 UTC 2018


On Tue, 10 Jul 2018 14:56:17 +0100
Daniel Stone <daniels at collabora.com> wrote:

> Add support for multiple modes to drm_output_propose_state. Currently we
> intend to operate in three modes: planes-only (no renderer buffer,
> client buffers in planes only), mixed-mode (promote client buffers to
> planes where possible, falling back to the renderer where not), and
> renderer-only (no plane usage at all).
> 
> We want to use the first (planes-only) mode where possible: it can avoid
> us having to allocate buffers for the renderer, and it also gives us the
> best chance of the optimal configuration, with no composition. In this
> mode, we walk the scene looking at all views, trying to put them in
> planes, and failing as soon as we find a view we cannot place in a
> plane.
> 
> In the second mode, rather than failing, we assign those views which
> cannot be on a plane to the renderer, and allow the renderer to
> composite them.
> 
> In the third mode, planes are not usable, so everything but the cursor
> goes to the renderer. We will use this when we cannot use the planes-only
> mode (because some views cannot be placed in planes), but also cannot
> use the 'mixed' mode because we have no renderer buffer yet. Since we
> walk the scene graph from top to bottom, using atomic modesetting we
> will determine if planes can be promoted in mixed mode by placing a
> renderer buffer at the bottom of the scene, placing a cursor buffer if
> applicable, then testing if we can add overlay planes to this mode.
> 
> Without a buffer from the renderer, we cannot do these tests, so we push
> everything through the renderer and then switch to mixed mode on the
> next repaint.
> 
> Signed-off-by: Daniel Stone <daniels at collabora.com>
> Tested-by: Emre Ucan <eucan at de.adit-jv.com>
> ---
>  libweston/compositor-drm.c | 86 +++++++++++++++++++++++++++-----------
>  1 file changed, 61 insertions(+), 25 deletions(-)
> 
> diff --git a/libweston/compositor-drm.c b/libweston/compositor-drm.c
> index 4a48e2d02..81fcd2412 100644
> --- a/libweston/compositor-drm.c
> +++ b/libweston/compositor-drm.c
> @@ -1939,16 +1939,25 @@ drm_output_assign_state(struct drm_output_state *state,
>  	}
>  }
>  
> +enum drm_output_propose_state_mode {
> +	DRM_OUTPUT_PROPOSE_STATE_MIXED, /**< mix renderer & planes */
> +	DRM_OUTPUT_PROPOSE_STATE_PLANES_ONLY, /**< only assign to planes */
> +	DRM_OUTPUT_PROPOSE_STATE_RENDERER_ONLY, /**< only assign to renderer & cursor */
> +};

This is good!

> +
>  static struct weston_plane *
>  drm_output_prepare_scanout_view(struct drm_output_state *output_state,
>  				struct weston_view *ev)
>  {
>  	struct drm_output *output = output_state->output;
> +	struct drm_backend *b = to_drm_backend(output->base.compositor);
>  	struct drm_plane *scanout_plane = output->scanout_plane;
>  	struct drm_plane_state *state;
>  	struct drm_fb *fb;
>  	pixman_box32_t *extents;
>  
> +	assert(!b->sprites_are_broken);
> +
>  	/* Check the view spans exactly the output size, calculated in the
>  	 * logical co-ordinate space. */
>  	extents = pixman_region32_extents(&ev->transform.boundingbox);
> @@ -3004,8 +3013,7 @@ drm_output_prepare_overlay_view(struct drm_output_state *output_state,
>  	struct drm_fb *fb;
>  	unsigned int i;
>  
> -	if (b->sprites_are_broken)
> -		return NULL;
> +	assert(!b->sprites_are_broken);
>  
>  	fb = drm_fb_get_from_view(output_state, ev);
>  	if (!fb)
> @@ -3119,10 +3127,9 @@ drm_output_prepare_cursor_view(struct drm_output_state *output_state,
>  	struct wl_shm_buffer *shmbuf;
>  	bool needs_update = false;
>  
> -	if (!plane)
> -		return NULL;
> +	assert(!b->cursors_are_broken);
>  
> -	if (b->cursors_are_broken)
> +	if (!plane)
>  		return NULL;
>  
>  	if (!plane->state_cur->complete)
> @@ -3257,13 +3264,17 @@ err:
>  
>  static struct drm_output_state *
>  drm_output_propose_state(struct weston_output *output_base,
> -			 struct drm_pending_state *pending_state)
> +			 struct drm_pending_state *pending_state,
> +			 enum drm_output_propose_state_mode mode)
>  {
>  	struct drm_output *output = to_drm_output(output_base);
> +	struct drm_backend *b = to_drm_backend(output_base->compositor);
>  	struct drm_output_state *state;
>  	struct weston_view *ev;
>  	pixman_region32_t surface_overlap, renderer_region, occluded_region;
>  	struct weston_plane *primary = &output_base->compositor->primary_plane;
> +	bool renderer_ok = (mode != DRM_OUTPUT_PROPOSE_STATE_PLANES_ONLY);
> +	bool planes_ok = (mode != DRM_OUTPUT_PROPOSE_STATE_RENDERER_ONLY);
>  
>  	assert(!output->state_last);
>  	state = drm_output_state_duplicate(output->state_cur,
> @@ -3336,7 +3347,10 @@ drm_output_propose_state(struct weston_output *output_base,
>  			next_plane = primary;
>  		pixman_region32_fini(&surface_overlap);
>  
> -		if (next_plane == NULL)
> +		/* The cursor plane is 'special' in the sense that we can still
> +		 * place it in the legacy API, and we gate that with a separate
> +		 * cursors_are_broken flag. */
> +		if (next_plane == NULL && !b->cursors_are_broken)
>  			next_plane = drm_output_prepare_cursor_view(state, ev);
>  
>  		if (next_plane == NULL && !drm_view_is_opaque(ev))
> @@ -3351,30 +3365,46 @@ drm_output_propose_state(struct weston_output *output_base,
>  		if (next_plane == NULL)
>  			next_plane = drm_output_prepare_overlay_view(state, ev);
>  
> -		if (next_plane == NULL)
> -			next_plane = primary;
> +		if (next_plane) {

This if-statement confuses me, it does not seem to have any purpose.

> +			/* If we have been assigned to an overlay or scanout
> +			 * plane, add this area to the occluded region, so
> +			 * other views are known to be behind it. The cursor
> +			 * plane, however, is special, in that it blends with
> +			 * the content underneath it: the area should neither
> +			 * be added to the renderer region nor the occluded
> +			 * region. */
> +			if (!output->cursor_plane ||
> +			    next_plane != &output->cursor_plane->base) {
> +				pixman_region32_union(&occluded_region,
> +						      &occluded_region,
> +						      &clipped_view);
> +				pixman_region32_fini(&clipped_view);
> +			}
> +			continue;

If next_plane == primary, then it seems we skip the renderer_region.
That's not good?

It also skips the renderer_ok check.

Otherwise this patch looks ok.


Thanks,
pq


> +		}
>  
> -		/* If we've been assigned to the 'primary' (renderer) plane,
> -		 * add this to our renderer region. If we have been assigned
> -		 * to the cursor plane, do nothing, as the cursor plane is
> -		 * blended with content underneath it. If neither, we have
> -		 * been assigned to an overlay plane, so add this view's
> -		 * area to the occluded region. */
> -		if (next_plane == primary)
> -			pixman_region32_union(&renderer_region,
> -					      &renderer_region,
> -					      &clipped_view);
> -		else if (!output->cursor_plane ||
> -			 next_plane != &output->cursor_plane->base)
> -			pixman_region32_union(&occluded_region,
> -					      &occluded_region,
> -					      &clipped_view);
> +		/* We have been assigned to the primary (renderer) plane:
> +		 * check if this is OK, and add ourselves to the renderer
> +		 * region if so. */
> +		if (!renderer_ok) {
> +			pixman_region32_fini(&clipped_view);
> +			goto err;
> +		}
> +		pixman_region32_union(&renderer_region,
> +				      &renderer_region,
> +				      &clipped_view);
>  		pixman_region32_fini(&clipped_view);
>  	}
>  	pixman_region32_fini(&renderer_region);
>  	pixman_region32_fini(&occluded_region);
>  
>  	return state;
> +
> +err:
> +	pixman_region32_fini(&renderer_region);
> +	pixman_region32_fini(&occluded_region);
> +	drm_output_state_free(state);
> +	return NULL;
>  }
>  
>  static void
> @@ -3387,8 +3417,14 @@ drm_assign_planes(struct weston_output *output_base, void *repaint_data)
>  	struct drm_plane_state *plane_state;
>  	struct weston_view *ev;
>  	struct weston_plane *primary = &output_base->compositor->primary_plane;
> +	enum drm_output_propose_state_mode mode;
> +
> +	if (b->sprites_are_broken)
> +		mode = DRM_OUTPUT_PROPOSE_STATE_RENDERER_ONLY;
> +	else
> +		mode = DRM_OUTPUT_PROPOSE_STATE_MIXED;
>  
> -	state = drm_output_propose_state(output_base, pending_state);
> +	state = drm_output_propose_state(output_base, pending_state, mode);
>  
>  	wl_list_for_each(ev, &output_base->compositor->view_list, link) {
>  		struct drm_plane *target_plane = NULL;

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