test: add a new test for layer priority

This test continuously updates a layer's FB for some time, and keeps another
layer static. The continously updated layer should be put in a plane.

The test is disabled for now because priorities aren't implemented yet.

test/meson.build

@@ -40,6 +40,9 @@ tests = {
 		'fb',
 		'new-layer',
 	],
+	'priority': [
+		#'basic',
+	],
 }
 
 foreach test_name, subtests : tests

test/test_priority.c

@@ -0,0 +1,88 @@
+#include <assert.h>
+#include <unistd.h>
+#include <libliftoff.h>
+#include <stdio.h>
+#include <string.h>
+#include "libdrm_mock.h"
+
+/* Number of page-flips before the plane allocation has stabilized */
+#define STABILIZE_PAGEFLIP_COUNT 600 /* 10s at 60FPS */
+
+static struct liftoff_layer *add_layer(struct liftoff_output *output,
+				       int x, int y, int width, int height)
+{
+	uint32_t fb_id;
+	struct liftoff_layer *layer;
+
+	layer = liftoff_layer_create(output);
+	fb_id = liftoff_mock_drm_create_fb(layer);
+	liftoff_layer_set_property(layer, "FB_ID", fb_id);
+	liftoff_layer_set_property(layer, "CRTC_X", x);
+	liftoff_layer_set_property(layer, "CRTC_Y", y);
+	liftoff_layer_set_property(layer, "CRTC_W", width);
+	liftoff_layer_set_property(layer, "CRTC_H", height);
+	liftoff_layer_set_property(layer, "SRC_X", 0);
+	liftoff_layer_set_property(layer, "SRC_Y", 0);
+	liftoff_layer_set_property(layer, "SRC_W", width << 16);
+	liftoff_layer_set_property(layer, "SRC_H", height << 16);
+
+	return layer;
+}
+
+int main(int argc, char *argv[]) {
+	struct liftoff_mock_plane *mock_plane;
+	int drm_fd;
+	struct liftoff_display *display;
+	struct liftoff_output *output;
+	struct liftoff_layer *layers[2], *layer;
+	uint32_t fbs[2];
+	drmModeAtomicReq *req;
+	bool ok;
+
+	liftoff_log_init(LIFTOFF_SILENT, NULL);
+
+	mock_plane = liftoff_mock_drm_create_plane(DRM_PLANE_TYPE_PRIMARY);
+	/* Plane incompatible with all layers */
+	liftoff_mock_drm_create_plane(DRM_PLANE_TYPE_CURSOR);
+
+	drm_fd = liftoff_mock_drm_open();
+	display = liftoff_display_create(drm_fd);
+	assert(display != NULL);
+
+	output = liftoff_output_create(display, liftoff_mock_drm_crtc_id);
+	layers[0] = add_layer(output, 0, 0, 1920, 1080);
+	layers[1] = add_layer(output, 0, 0, 1920, 1080);
+
+	/* All layers are compatible with the primary plane */
+	liftoff_mock_plane_add_compatible_layer(mock_plane, layers[0]);
+	liftoff_mock_plane_add_compatible_layer(mock_plane, layers[1]);
+
+	for (size_t i = 0; i < sizeof(layers) / sizeof(layers[0]); i++) {
+		/* We will continuously update layers[i]. After some time we
+		 * want to see it get a plane. */
+		layer = layers[i];
+		fprintf(stderr, "Testing layer %zu\n", i);
+
+		fbs[0] = liftoff_mock_drm_create_fb(layer);
+		fbs[1] = liftoff_mock_drm_create_fb(layer);
+
+		req = drmModeAtomicAlloc();
+		for (int j = 0; j < STABILIZE_PAGEFLIP_COUNT; j++) {
+			drmModeAtomicSetCursor(req, 0);
+
+			liftoff_layer_set_property(layer, "FB_ID", fbs[j % 2]);
+
+			ok = liftoff_display_apply(display, req);
+			assert(ok);
+		}
+
+		assert(liftoff_mock_plane_get_layer(mock_plane, req) == layer);
+
+		drmModeAtomicFree(req);
+	}
+
+	liftoff_display_destroy(display);
+	close(drm_fd);
+
+	return 0;
+}