[PATCH weston] compositor-fbdev: Drop intermediate shadow buffer

[Derek Foreman]

From: Sjoerd Simons <sjoerd.simons at collabora.co.uk>

Currently the fbdev compositor has its own shadow buffer when rendering
with pixman, causing the following copies to occur:

[pixman shadow buffer] -> [fbdev shadow buffer] -> [fbdev hardware]

As the pixman render already does all output translation when
compositing the intermediate shadow buffer really isn't needed, so drop
it.

As a side-effect this fixes updating the fbdev hardware for outputs not
starting at 0x0.

Signed-off-by: Sjoerd Simons <sjoerd.simons at collabora.co.uk>
---

Pekka and I were talking about this earlier and remembered seeing this patch.

I thought it had already landed, but apparently not.

All I've done is rebase it, will try to get around to reviewing it next week
as the pixman renderer is still uselessly allocating an extra shadow buffer.


 src/compositor-fbdev.c | 68 +++-----------------------------------------------
 1 file changed, 3 insertions(+), 65 deletions(-)

diff --git a/src/compositor-fbdev.c b/src/compositor-fbdev.c
index 57c54c2..8cffb6c 100644
--- a/src/compositor-fbdev.c
+++ b/src/compositor-fbdev.c
@@ -90,8 +90,6 @@ struct fbdev_output {
 
 	/* pixman details. */
 	pixman_image_t *hw_surface;
-	pixman_image_t *shadow_surface;
-	void *shadow_buf;
 	uint8_t depth;
 };
 
@@ -131,39 +129,11 @@ fbdev_output_repaint_pixman(struct weston_output *base, pixman_region32_t *damag
 {
 	struct fbdev_output *output = to_fbdev_output(base);
 	struct weston_compositor *ec = output->base.compositor;
-	pixman_box32_t *rects;
-	int nrects, i;
 
 	/* Repaint the damaged region onto the back buffer. */
-	pixman_renderer_output_set_buffer(base, output->shadow_surface);
+	pixman_renderer_output_set_buffer(base, output->hw_surface);
 	ec->renderer->repaint_output(base, damage);
 
-	/* Transform and composite onto the frame buffer. */
-	rects = pixman_region32_rectangles(damage, &nrects);
-
-	for (i = 0; i < nrects; i++) {
-		pixman_box32_t transformed_rect;
-		int width, height;
-
-		transformed_rect = weston_transformed_rect(base->width,
-							   base->height,
-							   base->transform,
-							   1, rects[i]);
-		width = transformed_rect.x2 - transformed_rect.x1;
-		height = transformed_rect.y2 - transformed_rect.y1;
-		pixman_image_composite32(PIXMAN_OP_SRC,
-			output->shadow_surface, /* src */
-			NULL /* mask */,
-			output->hw_surface, /* dest */
-			transformed_rect.x1, /* src_x */
-			transformed_rect.y1, /* src_y */
-			0, 0, /* mask_x, mask_y */
-			transformed_rect.x1, /* dest_x */
-			transformed_rect.y1, /* dest_y */
-			width, /* width */
-			height /* height */);
-	}
-
 	/* Update the damage region. */
 	pixman_region32_subtract(&ec->primary_plane.damage,
 	                         &ec->primary_plane.damage, damage);
@@ -489,8 +459,6 @@ fbdev_output_create(struct fbdev_backend *backend,
 	struct fbdev_output *output;
 	struct weston_config_section *section;
 	int fb_fd;
-	int width, height;
-	unsigned int bytes_per_pixel;
 	struct wl_event_loop *loop;
 	uint32_t config_transform;
 	char *s;
@@ -553,24 +521,9 @@ fbdev_output_create(struct fbdev_backend *backend,
 	                   config_transform,
 			   1);
 
-	width = output->mode.width;
-	height = output->mode.height;
-	bytes_per_pixel = output->fb_info.bits_per_pixel / 8;
-
-	output->shadow_buf = malloc(width * height * bytes_per_pixel);
-	output->shadow_surface =
-		pixman_image_create_bits(output->fb_info.pixel_format,
-		                         width, height,
-		                         output->shadow_buf,
-		                         width * bytes_per_pixel);
-	if (output->shadow_buf == NULL || output->shadow_surface == NULL) {
-		weston_log("Failed to create surface for frame buffer.\n");
-		goto out_hw_surface;
-	}
-
 	if (backend->use_pixman) {
 		if (pixman_renderer_output_create(&output->base) < 0)
-			goto out_shadow_surface;
+			goto out_hw_surface;
 	} else {
 		setenv("HYBRIS_EGLPLATFORM", "wayland", 1);
 		if (gl_renderer->output_create(&output->base,
@@ -578,11 +531,10 @@ fbdev_output_create(struct fbdev_backend *backend,
 					       gl_renderer->opaque_attribs,
 					       NULL, 0) < 0) {
 			weston_log("gl_renderer_output_create failed.\n");
-			goto out_shadow_surface;
+			goto out_hw_surface;
 		}
 	}
 
-
 	loop = wl_display_get_event_loop(backend->compositor->wl_display);
 	output->finish_frame_timer =
 		wl_event_loop_add_timer(loop, finish_frame_handler, output);
@@ -596,11 +548,7 @@ fbdev_output_create(struct fbdev_backend *backend,
 
 	return 0;
 
-out_shadow_surface:
-	pixman_image_unref(output->shadow_surface);
-	output->shadow_surface = NULL;
 out_hw_surface:
-	free(output->shadow_buf);
 	pixman_image_unref(output->hw_surface);
 	output->hw_surface = NULL;
 	weston_output_destroy(&output->base);
@@ -625,16 +573,6 @@ fbdev_output_destroy(struct weston_output *base)
 	if (backend->use_pixman) {
 		if (base->renderer_state != NULL)
 			pixman_renderer_output_destroy(base);
-
-		if (output->shadow_surface != NULL) {
-			pixman_image_unref(output->shadow_surface);
-			output->shadow_surface = NULL;
-		}
-
-		if (output->shadow_buf != NULL) {
-			free(output->shadow_buf);
-			output->shadow_buf = NULL;
-		}
 	} else {
 		gl_renderer->output_destroy(base);
 	}
-- 
2.6.2