compositor-drm: Fix compilation error caused by typo.
[profile/ivi/weston.git] / compositor / compositor-drm.c
index 4133c19..536760b 100644 (file)
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 
-#define GL_GLEXT_PROTOTYPES
-#define EGL_EGLEXT_PROTOTYPES
-#include <GLES2/gl2.h>
-#include <GLES2/gl2ext.h>
-#include <EGL/egl.h>
-#include <EGL/eglext.h>
+#include <gbm.h>
 
 #include "compositor.h"
 
@@ -48,22 +43,30 @@ struct drm_compositor {
        struct {
                int fd;
        } drm;
+       struct gbm_device *gbm;
        uint32_t crtc_allocator;
        uint32_t connector_allocator;
        struct tty *tty;
 };
 
+struct drm_mode {
+       struct wlsc_mode base;
+       drmModeModeInfo mode_info;
+};
+
 struct drm_output {
        struct wlsc_output   base;
 
-       drmModeModeInfo mode;
        uint32_t crtc_id;
        uint32_t connector_id;
        GLuint rbo[2];
        uint32_t fb_id[2];
        EGLImageKHR image[2];
+       struct gbm_bo *bo[2];
        uint32_t current;       
 
+       struct wlsc_surface *scanout_surface;
+
        uint32_t fs_surf_fb_id;
        uint32_t pending_fs_surf_fb_id;
 };
@@ -90,7 +93,6 @@ drm_output_present(struct wlsc_output *output_base)
        struct drm_output *output = (struct drm_output *) output_base;
        struct drm_compositor *c =
                (struct drm_compositor *) output->base.compositor;
-       int ret;
        uint32_t fb_id = 0;
 
        if (drm_output_prepare_render(&output->base))
@@ -99,22 +101,8 @@ drm_output_present(struct wlsc_output *output_base)
 
        output->current ^= 1;
 
-       if (output->base.scanout_surface) {
-               EGLint handle, stride;
-
-               eglExportDRMImageMESA(c->base.display,
-                                     output->base.scanout_surface->image,
-                                     NULL, &handle, &stride);
-
-               ret = drmModeAddFB(c->drm.fd,
-                                  output->base.width, output->base.height,
-                                  32, 32, stride, handle,
-                                  &output->fs_surf_fb_id);
-               if (ret)
-                       return -1;
-
-               printf("pageflip to fullscreen buffer: %d\n", handle);
-
+       if (output->scanout_surface != NULL) {
+               output->scanout_surface = NULL;
                fb_id = output->fs_surf_fb_id;
        } else {
                fb_id = output->fb_id[output->current ^ 1];
@@ -151,8 +139,8 @@ page_flip_handler(int fd, unsigned int frame,
 }
 
 static int
-drm_output_image_is_scanoutable(struct wlsc_output *output_base,
-                               EGLImageKHR image)
+drm_output_prepare_scanout_surface(struct wlsc_output *output_base,
+                                  struct wlsc_surface *es)
 {
        struct drm_output *output = (struct drm_output *) output_base;
        struct drm_compositor *c =
@@ -160,36 +148,58 @@ drm_output_image_is_scanoutable(struct wlsc_output *output_base,
        EGLint handle, stride;
        int ret;
        uint32_t fb_id = 0;
+       struct gbm_bo *bo;
+
+       if (es->x != output->base.x ||
+           es->y != output->base.y ||
+           es->width != output->base.current->width ||
+           es->height != output->base.current->height ||
+           es->image == EGL_NO_IMAGE_KHR)
+               return -1;
 
-       eglExportDRMImageMESA(c->base.display, image,
-                             NULL, &handle, &stride);
+       bo = gbm_bo_create_from_egl_image(c->gbm,
+                                         c->base.display, es->image,
+                                         es->width, es->height,
+                                         GBM_BO_USE_SCANOUT);
+
+       handle = gbm_bo_get_handle(bo).s32;
+       stride = gbm_bo_get_pitch(bo);
+
+       gbm_bo_destroy(bo);
+
+       if (handle == 0)
+               return -1;
 
        ret = drmModeAddFB(c->drm.fd,
-                          output->base.width, output->base.height,
-                          32, 32, stride, handle,
-                          &fb_id);
+                          output->base.current->width,
+                          output->base.current->height,
+                          32, 32, stride, handle, &fb_id);
+
        if (ret)
-               return 0;
+               return -1;
 
-       /* FIXME: change interface to keep this fb_id,
-        * to be used directly in next pageflip? */
-       if (fb_id)
-               drmModeRmFB(c->drm.fd, fb_id);
+       output->fs_surf_fb_id = fb_id;
+       output->scanout_surface = es;
 
-       return fb_id != 0;
+       return 0;
 }
 
 static int
 drm_output_set_cursor(struct wlsc_output *output_base,
-                     struct wl_input_device *input)
+                     struct wlsc_input_device *eid)
 {
        struct drm_output *output = (struct drm_output *) output_base;
        struct drm_compositor *c =
                (struct drm_compositor *) output->base.compositor;
-       struct wlsc_input_device *eid = (struct wlsc_input_device *) input;
        EGLint handle, stride;
        int ret = -1;
        pixman_region32_t cursor_region;
+       struct gbm_bo *bo;
+
+       if (eid == NULL) {
+               drmModeSetCursor(c->drm.fd, output->crtc_id, 0, 0, 0);
+               return 0;
+       }
 
        pixman_region32_init_rect(&cursor_region,
                                  eid->sprite->x, eid->sprite->y,
@@ -197,12 +207,11 @@ drm_output_set_cursor(struct wlsc_output *output_base,
 
        pixman_region32_intersect_rect(&cursor_region, &cursor_region,
                                       output->base.x, output->base.y,
-                                      output->base.width, output->base.height);
+                                      output->base.current->width,
+                                      output->base.current->height);
 
-       if (!pixman_region32_not_empty(&cursor_region)) {
-               ret = 0;
+       if (!pixman_region32_not_empty(&cursor_region))
                goto out;
-       }
 
        if (eid->sprite->image == EGL_NO_IMAGE_KHR)
                goto out;
@@ -210,8 +219,15 @@ drm_output_set_cursor(struct wlsc_output *output_base,
        if (eid->sprite->width > 64 || eid->sprite->height > 64)
                goto out;
        
-       eglExportDRMImageMESA(c->base.display, eid->sprite->image,
-                             NULL, &handle, &stride);
+       bo = gbm_bo_create_from_egl_image(c->gbm,
+                                         c->base.display,
+                                         eid->sprite->image, 64, 64,
+                                         GBM_BO_USE_CURSOR_64X64);
+
+       handle = gbm_bo_get_handle(bo).s32;
+       stride = gbm_bo_get_pitch(bo);
+
+       gbm_bo_destroy(bo);
 
        if (stride != 64 * 4) {
                fprintf(stderr, "info: cursor stride is != 64\n");
@@ -232,8 +248,6 @@ drm_output_set_cursor(struct wlsc_output *output_base,
                goto out;
        }
 
-       printf("info: set hardware cursor\n");
-
 out:
        pixman_region32_fini(&cursor_region);
        if (ret)
@@ -241,7 +255,7 @@ out:
        return ret;
 }
 
-static void
+static int
 on_drm_input(int fd, uint32_t mask, void *data)
 {
        drmEventContext evctx;
@@ -250,6 +264,8 @@ on_drm_input(int fd, uint32_t mask, void *data)
        evctx.version = DRM_EVENT_CONTEXT_VERSION;
        evctx.page_flip_handler = page_flip_handler;
        drmHandleEvent(fd, &evctx);
+
+       return 1;
 }
 
 static int
@@ -272,8 +288,10 @@ init_egl(struct drm_compositor *ec, struct udev_device *device)
                return -1;
        }
 
+       setenv("EGL_PLATFORM", "drm", 1);
        ec->drm.fd = fd;
-       ec->base.display = eglGetDRMDisplayMESA(ec->drm.fd);
+       ec->gbm = gbm_create_device(ec->drm.fd);
+       ec->base.display = eglGetDisplay(ec->gbm);
        if (ec->base.display == NULL) {
                fprintf(stderr, "failed to create display\n");
                return -1;
@@ -321,6 +339,46 @@ static drmModeModeInfo builtin_1024x768 = {
        "1024x768"
 };
 
+
+static int
+drm_output_add_mode(struct drm_output *output, drmModeModeInfo *info)
+{
+       struct drm_mode *mode;
+
+       mode = malloc(sizeof *mode);
+       if (mode == NULL)
+               return -1;
+
+       mode->base.flags = 0;
+       mode->base.width = info->hdisplay;
+       mode->base.height = info->vdisplay;
+       mode->base.refresh = info->vrefresh;
+       mode->mode_info = *info;
+       wl_list_insert(output->base.mode_list.prev, &mode->base.link);
+
+       return 0;
+}
+
+static int
+drm_subpixel_to_wayland(int drm_value)
+{
+       switch (drm_value) {
+       default:
+       case DRM_MODE_SUBPIXEL_UNKNOWN:
+               return WL_OUTPUT_SUBPIXEL_UNKNOWN;
+       case DRM_MODE_SUBPIXEL_NONE:
+               return WL_OUTPUT_SUBPIXEL_NONE;
+       case DRM_MODE_SUBPIXEL_HORIZONTAL_RGB:
+               return WL_OUTPUT_SUBPIXEL_HORIZONTAL_RGB;
+       case DRM_MODE_SUBPIXEL_HORIZONTAL_BGR:
+               return WL_OUTPUT_SUBPIXEL_HORIZONTAL_BGR;
+       case DRM_MODE_SUBPIXEL_VERTICAL_RGB:
+               return WL_OUTPUT_SUBPIXEL_VERTICAL_RGB;
+       case DRM_MODE_SUBPIXEL_VERTICAL_BGR:
+               return WL_OUTPUT_SUBPIXEL_VERTICAL_BGR;
+       }
+}
+
 static int
 create_output_for_connector(struct drm_compositor *ec,
                            drmModeRes *resources,
@@ -328,25 +386,10 @@ create_output_for_connector(struct drm_compositor *ec,
                            int x, int y)
 {
        struct drm_output *output;
+       struct drm_mode *drm_mode;
        drmModeEncoder *encoder;
-       drmModeModeInfo *mode;
        int i, ret;
-       EGLint handle, stride, attribs[] = {
-               EGL_WIDTH,              0,
-               EGL_HEIGHT,             0,
-               EGL_DRM_BUFFER_FORMAT_MESA,     EGL_DRM_BUFFER_FORMAT_ARGB32_MESA,
-               EGL_DRM_BUFFER_USE_MESA,        EGL_DRM_BUFFER_USE_SCANOUT_MESA,
-               EGL_NONE
-       };
-
-       output = malloc(sizeof *output);
-       if (output == NULL)
-               return -1;
-
-       if (connector->count_modes > 0) 
-               mode = &connector->modes[0];
-       else
-               mode = &builtin_1024x768;
+       unsigned handle, stride;
 
        encoder = drmModeGetEncoder(ec->drm.fd, connector->encoders[0]);
        if (encoder == NULL) {
@@ -364,16 +407,36 @@ create_output_for_connector(struct drm_compositor *ec,
                return -1;
        }
 
+       output = malloc(sizeof *output);
+       if (output == NULL)
+               return -1;
+
        memset(output, 0, sizeof *output);
-       wlsc_output_init(&output->base, &ec->base, x, y,
-                        mode->hdisplay, mode->vdisplay, 0);
+       output->base.subpixel = drm_subpixel_to_wayland(connector->subpixel);
+       output->base.make = "unknown";
+       output->base.model = "unknown";
+       wl_list_init(&output->base.mode_list);
 
        output->crtc_id = resources->crtcs[i];
        ec->crtc_allocator |= (1 << output->crtc_id);
-
        output->connector_id = connector->connector_id;
        ec->connector_allocator |= (1 << output->connector_id);
-       output->mode = *mode;
+
+       for (i = 0; i < connector->count_modes; i++)
+               drm_output_add_mode(output, &connector->modes[i]);
+       if (connector->count_modes == 0)
+               drm_output_add_mode(output, &builtin_1024x768);
+
+       drm_mode = container_of(output->base.mode_list.next,
+                               struct drm_mode, base.link);
+       output->base.current = &drm_mode->base;
+       drm_mode->base.flags =
+               WL_OUTPUT_MODE_CURRENT | WL_OUTPUT_MODE_PREFERRED;
+
+       wlsc_output_init(&output->base, &ec->base, x, y,
+                        connector->mmWidth, connector->mmHeight, 0);
+
+       wl_list_insert(ec->base.output_list.prev, &output->base.link);
 
        drmModeFreeEncoder(encoder);
 
@@ -381,17 +444,26 @@ create_output_for_connector(struct drm_compositor *ec,
        for (i = 0; i < 2; i++) {
                glBindRenderbuffer(GL_RENDERBUFFER, output->rbo[i]);
 
-               attribs[1] = output->base.width;
-               attribs[3] = output->base.height;
-               output->image[i] =
-                       eglCreateDRMImageMESA(ec->base.display, attribs);
-               glEGLImageTargetRenderbufferStorageOES(GL_RENDERBUFFER,
-                                                      output->image[i]);
-               eglExportDRMImageMESA(ec->base.display, output->image[i],
-                                     NULL, &handle, &stride);
+               output->bo[i] =
+                       gbm_bo_create(ec->gbm,
+                                     output->base.current->width,
+                                     output->base.current->height,
+                                     GBM_BO_FORMAT_XRGB8888,
+                                     GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING);
+               output->image[i] = ec->base.create_image(ec->base.display,
+                                                        NULL,
+                                                        EGL_NATIVE_PIXMAP_KHR,
+                                                        output->bo[i], NULL);
+
+
+               ec->base.image_target_renderbuffer_storage(GL_RENDERBUFFER,
+                                                          output->image[i]);
+               stride = gbm_bo_get_pitch(output->bo[i]);
+               handle = gbm_bo_get_handle(output->bo[i]).u32;
 
                ret = drmModeAddFB(ec->drm.fd,
-                                  output->base.width, output->base.height,
+                                  output->base.current->width,
+                                  output->base.current->height,
                                   32, 32, stride, handle, &output->fb_id[i]);
                if (ret) {
                        fprintf(stderr, "failed to add fb %d: %m\n", i);
@@ -406,19 +478,20 @@ create_output_for_connector(struct drm_compositor *ec,
                                  output->rbo[output->current]);
        ret = drmModeSetCrtc(ec->drm.fd, output->crtc_id,
                             output->fb_id[output->current ^ 1], 0, 0,
-                            &output->connector_id, 1, &output->mode);
+                            &output->connector_id, 1,
+                            &drm_mode->mode_info);
        if (ret) {
                fprintf(stderr, "failed to set mode: %m\n");
                return -1;
        }
 
+       output->scanout_surface = NULL;
        output->base.prepare_render = drm_output_prepare_render;
        output->base.present = drm_output_present;
-       output->base.image_is_scanoutable = drm_output_image_is_scanoutable;
+       output->base.prepare_scanout_surface =
+               drm_output_prepare_scanout_surface;
        output->base.set_hardware_cursor = drm_output_set_cursor;
 
-       wl_list_insert(ec->base.output_list.prev, &output->base.link);
-
        return 0;
 }
 
@@ -443,13 +516,15 @@ create_outputs(struct drm_compositor *ec, int option_connector)
 
                if (connector->connection == DRM_MODE_CONNECTED &&
                    (option_connector == 0 ||
-                    connector->connector_id == option_connector))
+                    connector->connector_id == option_connector)) {
                        if (create_output_for_connector(ec, resources,
                                                        connector, x, y) < 0)
                                return -1;
 
-               x += container_of(ec->base.output_list.prev, struct wlsc_output,
-                                 link)->width;
+                       x += container_of(ec->base.output_list.prev,
+                                         struct wlsc_output,
+                                         link)->current->width;
+               }
 
                drmModeFreeConnector(connector);
        }
@@ -480,7 +555,7 @@ destroy_output(struct drm_output *output)
        glDeleteRenderbuffers(2, output->rbo);
 
        for (i = 0; i < 2; i++) {
-               eglDestroyImageKHR(ec->base.display, output->image[i]);
+               ec->base.destroy_image(ec->base.display, output->image[i]);
                drmModeRmFB(ec->drm.fd, output->fb_id[i]);
        }
        
@@ -530,7 +605,7 @@ update_outputs(struct drm_compositor *ec)
 
                        /* XXX: not yet needed, we die with 0 outputs */
                        if (!wl_list_empty(&ec->base.output_list))
-                               x = last_output->x + last_output->width;
+                               x = last_output->x + last_output->current->width;
                        else
                                x = 0;
                        y = 0;
@@ -558,7 +633,7 @@ update_outputs(struct drm_compositor *ec)
                                disconnects &= ~(1 << output->connector_id);
                                printf("connector %d disconnected\n",
                                       output->connector_id);
-                               x_offset += output->base.width;
+                               x_offset += output->base.current->width;
                                destroy_output(output);
                        }
                }
@@ -583,7 +658,7 @@ udev_event_is_hotplug(struct udev_device *device)
        return strcmp(udev_list_entry_get_value(hotplug_entry), "1") == 0;
 }
 
-static void
+static int
 udev_drm_event(int fd, uint32_t mask, void *data)
 {
        struct drm_compositor *ec = data;
@@ -595,48 +670,51 @@ udev_drm_event(int fd, uint32_t mask, void *data)
                update_outputs(ec);
 
        udev_device_unref(event);
+
+       return 1;
 }
 
 static EGLImageKHR
 drm_compositor_create_cursor_image(struct wlsc_compositor *ec,
                                   int32_t width, int32_t height)
 {
-       EGLint image_attribs[] = {
-               EGL_WIDTH, 0,
-               EGL_HEIGHT, 0,
-               EGL_DRM_BUFFER_FORMAT_MESA, EGL_DRM_BUFFER_FORMAT_ARGB32_MESA,
-               0, 0,
-               EGL_NONE
-       };
-       EGLint stride, name;
-       EGLImageKHR tmp_image, image;
+       struct drm_compositor *c = (struct drm_compositor *) ec;
+       struct gbm_bo *bo;
+       EGLImageKHR image;
+       uint32_t *pixels;
+       GLuint tex;
 
        if (width > 64 || height > 64)
                return EGL_NO_IMAGE_KHR;
 
-       image_attribs[1] = 64;
-       image_attribs[3] = 64;
-       image_attribs[6] = EGL_DRM_BUFFER_USE_MESA;
-       image_attribs[7] = EGL_DRM_BUFFER_USE_SCANOUT_MESA;
-
-       tmp_image = eglCreateDRMImageMESA(ec->display, image_attribs);
+       bo = gbm_bo_create(c->gbm,
+                          /* width, height, */ 64, 64,
+                          GBM_BO_FORMAT_ARGB8888,
+                          GBM_BO_USE_CURSOR_64X64 | GBM_BO_USE_RENDERING);
 
-       eglExportDRMImageMESA(ec->display, tmp_image, &name, NULL, &stride);
+       image = ec->create_image(c->base.display, NULL,
+                                EGL_NATIVE_PIXMAP_KHR, bo, NULL);
+       gbm_bo_destroy(bo);
 
-       if (stride == 64)
-               return tmp_image;
+       /* If the requested size is smaller than the allocated one, make the
+        * whole image transparent. */
+       if (width != 64 || height != 64) {
+               pixels = calloc(64 * 64, sizeof *pixels);
 
-       /* recreate image width stide 64 forced */
-       image_attribs[1] = width;
-       image_attribs[3] = height;
-       image_attribs[6] = EGL_DRM_BUFFER_STRIDE_MESA;
-       image_attribs[7] = 64;
+               glGenTextures(1, &tex);
+               glBindTexture(GL_TEXTURE_2D, tex);
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 
-       image = eglCreateImageKHR(ec->display, EGL_NO_CONTEXT, EGL_DRM_BUFFER_MESA,
-                                 (EGLClientBuffer)(intptr_t) name, image_attribs);
-       eglExportDRMImageMESA(ec->display, image, &name, NULL, &stride);
+               c->base.image_target_texture_2d(GL_TEXTURE_2D, image);
+               glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 64, 64,
+                               GL_BGRA_EXT, GL_UNSIGNED_BYTE, pixels);
 
-       eglDestroyImageKHR(ec->display, tmp_image);
+               glDeleteTextures(1, &tex);
+               free(pixels);
+       }
 
        return image;
 }
@@ -651,14 +729,42 @@ drm_destroy(struct wlsc_compositor *ec)
        free(d);
 }
 
-struct wlsc_compositor *
-drm_compositor_create(struct wl_display *display, int connector)
+static void
+vt_func(struct wlsc_compositor *compositor, int event)
+{
+       struct drm_compositor *ec = (struct drm_compositor *) compositor;
+       struct wlsc_output *output;
+
+       switch (event) {
+       case TTY_ENTER_VT:
+               compositor->focus = 1;
+               drmSetMaster(ec->drm.fd);
+               compositor->state = WLSC_COMPOSITOR_ACTIVE;
+               wlsc_compositor_damage_all(compositor);
+               break;
+       case TTY_LEAVE_VT:
+               compositor->focus = 0;
+               compositor->state = WLSC_COMPOSITOR_SLEEPING;
+               drmDropMaster(ec->drm.fd);
+
+               wl_list_for_each(output, &ec->base.output_list, link)
+                       drm_output_set_cursor(output, NULL);
+
+               break;
+       };
+}
+
+static const char default_seat[] = "seat0";
+
+static struct wlsc_compositor *
+drm_compositor_create(struct wl_display *display,
+                     int connector, const char *seat)
 {
        struct drm_compositor *ec;
        struct udev_enumerate *e;
         struct udev_list_entry *entry;
-       struct udev_device *device;
-       const char *path;
+       struct udev_device *device, *drm_device;
+       const char *path, *device_seat;
        struct wl_event_loop *loop;
 
        ec = malloc(sizeof *ec);
@@ -674,27 +780,38 @@ drm_compositor_create(struct wl_display *display, int connector)
 
        e = udev_enumerate_new(ec->udev);
        udev_enumerate_add_match_subsystem(e, "drm");
-       udev_enumerate_add_match_property(e, "WAYLAND_SEAT", "1");
+
         udev_enumerate_scan_devices(e);
-       device = NULL;
+       drm_device = NULL;
         udev_list_entry_foreach(entry, udev_enumerate_get_list_entry(e)) {
                path = udev_list_entry_get_name(entry);
                device = udev_device_new_from_syspath(ec->udev, path);
-               break;
+                device_seat =
+                       udev_device_get_property_value(device, "ID_SEAT");
+               if (!device_seat)
+                       device_seat = default_seat;
+               if (strcmp(device_seat, seat) == 0) {
+                       drm_device = device;
+                       break;
+               }
+               udev_device_unref(device);
        }
+
         udev_enumerate_unref(e);
 
-       if (device == NULL) {
+       if (drm_device == NULL) {
                fprintf(stderr, "no drm device found\n");
                return NULL;
        }
 
        ec->base.wl_display = display;
-       if (init_egl(ec, device) < 0) {
+       if (init_egl(ec, drm_device) < 0) {
                fprintf(stderr, "failed to initialize egl\n");
                return NULL;
        }
 
+       udev_device_unref(drm_device);
+
        ec->base.destroy = drm_destroy;
        ec->base.create_cursor_image = drm_compositor_create_cursor_image;
 
@@ -712,13 +829,13 @@ drm_compositor_create(struct wl_display *display, int connector)
                return NULL;
        }
 
-       evdev_input_add_devices(&ec->base, ec->udev);
+       evdev_input_add_devices(&ec->base, ec->udev, seat);
 
        loop = wl_display_get_event_loop(ec->base.wl_display);
        ec->drm_source =
                wl_event_loop_add_fd(loop, ec->drm.fd,
                                     WL_EVENT_READABLE, on_drm_input, ec);
-       ec->tty = tty_create(&ec->base);
+       ec->tty = tty_create(&ec->base, vt_func);
 
        ec->udev_monitor = udev_monitor_new_from_netlink(ec->udev, "udev");
        if (ec->udev_monitor == NULL) {
@@ -738,3 +855,31 @@ drm_compositor_create(struct wl_display *display, int connector)
 
        return &ec->base;
 }
+
+struct wlsc_compositor *
+backend_init(struct wl_display *display, char *options);
+
+WL_EXPORT struct wlsc_compositor *
+backend_init(struct wl_display *display, char *options)
+{
+       int connector = 0, i;
+       const char *seat;
+       char *p, *value;
+
+       static char * const tokens[] = { "connector", "seat", NULL };
+       
+       p = options;
+       seat = default_seat;
+       while (i = getsubopt(&p, tokens, &value), i != -1) {
+               switch (i) {
+               case 0:
+                       connector = strtol(value, NULL, 0);
+                       break;
+               case 1:
+                       seat = value;
+                       break;
+               }
+       }
+
+       return drm_compositor_create(display, connector, seat);
+}