[profile/ivi/weston-ivi-shell.git] / src / compositor-rpi.c

/*
 * Copyright © 2008-2011 Kristian Høgsberg
 * Copyright © 2011 Intel Corporation
 * Copyright © 2012-2013 Raspberry Pi Foundation
 *
 * Permission to use, copy, modify, distribute, and sell this software and
 * its documentation for any purpose is hereby granted without fee, provided
 * that the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of the copyright holders not be used in
 * advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission.  The copyright holders make
 * no representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
 * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
 * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#define _GNU_SOURCE

#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>

#include <libudev.h>

#include "config.h"

#ifdef HAVE_BCM_HOST
#  include <bcm_host.h>
#else
#  include "rpi-bcm-stubs.h"
#endif

#include "compositor.h"
#include "rpi-renderer.h"
#include "evdev.h"

/*
 * Dispmanx API offers alpha-blended overlays for hardware compositing.
 * The final composite consists of dispmanx elements, and their contents:
 * the dispmanx resource assigned to the element. The elements may be
 * scanned out directly, or composited to a temporary surface, depending on
 * how the firmware decides to handle the scene. Updates to multiple elements
 * may be queued in a single dispmanx update object, resulting in atomic and
 * vblank synchronized display updates.
 *
 * To avoid tearing and display artifacts, the current dispmanx resource in a
 * dispmanx element must not be touched. Therefore each element must be
 * double-buffered, using two resources, the front and the back. The update
 * sequence is:
 * 0. the front resource is already in-use, the back resource is unused
 * 1. write data into the back resource
 * 2. submit an element update, back becomes in-use
 * 3. swap back and front pointers (both are in-use now)
 * 4. wait for update_submit completion, the new back resource becomes unused
 *
 * A resource may be destroyed only, when the update removing the element has
 * completed. Otherwise you risk showing an incomplete composition.
 *
 * The dispmanx element used as the native window for EGL does not need
 * manually allocated resources, EGL does double-buffering internally.
 * Unfortunately it also means, that we cannot alternate between two
 * buffers like the DRM backend does, since we have no control over what
 * resources EGL uses. We are forced to use EGL_BUFFER_PRESERVED as the
 * EGL_SWAP_BEHAVIOR to avoid repainting the whole output every frame.
 *
 * We also cannot bundle eglSwapBuffers into our own display update, which
 * means that Weston's primary plane updates and the overlay updates may
 * happen unsynchronized.
 */

#ifndef ELEMENT_CHANGE_LAYER
/* copied from interface/vmcs_host/vc_vchi_dispmanx.h of userland.git */
#define ELEMENT_CHANGE_LAYER          (1<<0)
#define ELEMENT_CHANGE_OPACITY        (1<<1)
#define ELEMENT_CHANGE_DEST_RECT      (1<<2)
#define ELEMENT_CHANGE_SRC_RECT       (1<<3)
#define ELEMENT_CHANGE_MASK_RESOURCE  (1<<4)
#define ELEMENT_CHANGE_TRANSFORM      (1<<5)
#endif

/* Enabling this debugging incurs a significant performance hit */
#if 0
#define DBG(...) \
        weston_log(__VA_ARGS__)
#else
#define DBG(...) do {} while (0)
#endif

/* If we had a fully featured vc_dispmanx_resource_write_data()... */
/*#define HAVE_RESOURCE_WRITE_DATA_RECT 1*/

struct rpi_compositor;
struct rpi_output;

struct rpi_resource {
        DISPMANX_RESOURCE_HANDLE_T handle;
        int width;
        int height; /* height of the image (valid pixel data) */
        int stride; /* bytes */
        int buffer_height; /* height of the buffer */
        VC_IMAGE_TYPE_T ifmt;
};

struct rpi_element {
        struct wl_list link;
        struct weston_plane plane;
        struct rpi_output *output;

        DISPMANX_ELEMENT_HANDLE_T handle;
        int layer;
        int need_swap;
        int single_buffer;

        struct rpi_resource resources[2];
        struct rpi_resource *front;
        struct rpi_resource *back;
        pixman_region32_t prev_damage;

        struct weston_surface *surface;
        struct wl_listener surface_destroy_listener;
};

struct rpi_flippipe {
        int readfd;
        int writefd;
        struct wl_event_source *source;
};

struct rpi_output {
        struct rpi_compositor *compositor;
        struct weston_output base;
        int single_buffer;

        struct weston_mode mode;
        struct rpi_flippipe flippipe;

        DISPMANX_DISPLAY_HANDLE_T display;

        struct wl_list element_list; /* struct rpi_element */
        struct wl_list old_element_list; /* struct rpi_element */
};

struct rpi_seat {
        struct weston_seat base;
        struct wl_list devices_list;

        struct udev_monitor *udev_monitor;
        struct wl_event_source *udev_monitor_source;
        char *seat_id;
};

struct rpi_compositor {
        struct weston_compositor base;
        uint32_t prev_state;

        struct udev *udev;
        struct tty *tty;

        int max_planes; /* per output, really */
        int single_buffer;
};

static inline struct rpi_output *
to_rpi_output(struct weston_output *base)
{
        return container_of(base, struct rpi_output, base);
}

static inline struct rpi_seat *
to_rpi_seat(struct weston_seat *base)
{
        return container_of(base, struct rpi_seat, base);
}

static inline struct rpi_compositor *
to_rpi_compositor(struct weston_compositor *base)
{
        return container_of(base, struct rpi_compositor, base);
}

static inline int
int_max(int a, int b)
{
        return a > b ? a : b;
}

static void
rpi_resource_init(struct rpi_resource *resource)
{
        resource->handle = DISPMANX_NO_HANDLE;
}

static void
rpi_resource_release(struct rpi_resource *resource)
{
        if (resource->handle == DISPMANX_NO_HANDLE)
                return;

        vc_dispmanx_resource_delete(resource->handle);
        DBG("resource %p release\n", resource);
        resource->handle = DISPMANX_NO_HANDLE;
}

static int
rpi_resource_realloc(struct rpi_resource *resource, VC_IMAGE_TYPE_T ifmt,
                     int width, int height, int stride, int buffer_height)
{
        uint32_t dummy;

        if (resource->handle != DISPMANX_NO_HANDLE &&
            resource->width == width &&
            resource->height == height &&
            resource->stride == stride &&
            resource->buffer_height == buffer_height &&
            resource->ifmt == ifmt)
                return 0;

        rpi_resource_release(resource);

        /* NOTE: if stride is not a multiple of 16 pixels in bytes,
         * the vc_image_* functions may break. Dispmanx elements
         * should be fine, though. Buffer_height probably has similar
         * constraints, too.
         */
        resource->handle =
                vc_dispmanx_resource_create(ifmt,
                                            width | (stride << 16),
                                            height | (buffer_height << 16),
                                            &dummy);
        if (resource->handle == DISPMANX_NO_HANDLE)
                return -1;

        resource->width = width;
        resource->height = height;
        resource->stride = stride;
        resource->buffer_height = buffer_height;
        resource->ifmt = ifmt;
        DBG("resource %p alloc\n", resource);
        return 0;
}

static VC_IMAGE_TYPE_T
shm_buffer_get_vc_format(struct wl_buffer *buffer)
{
        switch (wl_shm_buffer_get_format(buffer)) {
        case WL_SHM_FORMAT_XRGB8888:
                return VC_IMAGE_XRGB8888;
        case WL_SHM_FORMAT_ARGB8888:
                return VC_IMAGE_ARGB8888;
        default:
                /* invalid format */
                return VC_IMAGE_MIN;
        }
}

static int
rpi_resource_update(struct rpi_resource *resource, struct wl_buffer *buffer,
                    pixman_region32_t *region)
{
        pixman_region32_t write_region;
        pixman_box32_t *r;
        VC_RECT_T rect;
        VC_IMAGE_TYPE_T ifmt;
        uint32_t *pixels;
        int width;
        int height;
        int stride;
        int ret;
#ifdef HAVE_RESOURCE_WRITE_DATA_RECT
        int n;
#endif

        if (!buffer)
                return -1;

        ifmt = shm_buffer_get_vc_format(buffer);
        width = wl_shm_buffer_get_width(buffer);
        height = wl_shm_buffer_get_height(buffer);
        stride = wl_shm_buffer_get_stride(buffer);
        pixels = wl_shm_buffer_get_data(buffer);

        if (rpi_resource_realloc(resource, ifmt, width, height,
                                 stride, height) < 0)
                return -1;

        pixman_region32_init(&write_region);
        pixman_region32_intersect_rect(&write_region, region,
                                       0, 0, width, height);

#ifdef HAVE_RESOURCE_WRITE_DATA_RECT
        /* XXX: Can this do a format conversion, so that scanout does not have to? */
        r = pixman_region32_rectangles(&write_region, &n);
        while (n--) {
                vc_dispmanx_rect_set(&rect, r[n].x1, r[n].y1,
                                     r[n].x2 - r[n].x1, r[n].y2 - r[n].y1);

                ret = vc_dispmanx_resource_write_data_rect(resource->handle,
                                                           ifmt, stride,
                                                           pixels, &rect,
                                                           rect.x, rect.y);
                DBG("%s: %p %ux%u@%u,%u, ret %d\n", __func__, resource,
                    rect.width, rect.height, rect.x, rect.y, ret);
                if (ret)
                        break;
        }
#else
        /* vc_dispmanx_resource_write_data() ignores ifmt,
         * rect.x, rect.width, and uses stride only for computing
         * the size of the transfer as rect.height * stride.
         * Therefore we can only write rows starting at x=0.
         * To be able to write more than one scanline at a time,
         * the resource must have been created with the same stride
         * as used here, and we must write full scanlines.
         */

        r = pixman_region32_extents(&write_region);
        vc_dispmanx_rect_set(&rect, 0, r->y1, width, r->y2 - r->y1);
        ret = vc_dispmanx_resource_write_data(resource->handle, ifmt,
                                               stride, pixels, &rect);
        DBG("%s: %p %ux%u@%u,%u, ret %d\n", __func__, resource,
            width, r->y2 - r->y1, 0, r->y1, ret);
#endif

        pixman_region32_fini(&write_region);

        return ret ? -1 : 0;
}

static void
rpi_element_handle_surface_destroy(struct wl_listener *listener, void *data)
{
        struct rpi_element *element =
                container_of(listener, struct rpi_element,
                             surface_destroy_listener);

        element->surface = NULL;
}

static struct rpi_element *
rpi_element_create(struct rpi_output *output, struct weston_surface *surface)
{
        struct rpi_element *element;

        element = calloc(1, sizeof *element);
        if (!element)
                return NULL;

        element->output = output;
        element->single_buffer = output->single_buffer;
        element->handle = DISPMANX_NO_HANDLE;
        rpi_resource_init(&element->resources[0]);
        rpi_resource_init(&element->resources[1]);
        element->front = &element->resources[0];

        if (element->single_buffer) {
                element->back = element->front;
        } else {
                element->back = &element->resources[1];
        }

        pixman_region32_init(&element->prev_damage);

        weston_plane_init(&element->plane, floor(surface->geometry.x),
                          floor(surface->geometry.y));

        element->surface = surface;
        element->surface_destroy_listener.notify =
                rpi_element_handle_surface_destroy;
        wl_signal_add(&surface->resource.destroy_signal,
                      &element->surface_destroy_listener);

        wl_list_insert(output->element_list.prev, &element->link);

        return element;
}

static void
rpi_element_destroy(struct rpi_element *element)
{
        struct weston_surface *surface = element->surface;

        if (surface) {
                if (surface->plane == &element->plane) {
                        /* If a surface, that was on a plane, gets hidden,
                         * it will not appear in the repaint surface list,
                         * is never considered in rpi_output_assign_planes(),
                         * and hence can stay assigned to this element's plane.
                         * We need to reassign it here.
                         */
                        DBG("surface %p (%dx%d@%.1f,%.1f) to primary plane*\n",
                            surface,
                            surface->geometry.width, surface->geometry.height,
                            surface->geometry.x, surface->geometry.y);
                        weston_surface_move_to_plane(surface,
                                &surface->compositor->primary_plane);
                }
                wl_list_remove(&element->surface_destroy_listener.link);
        }

        wl_list_remove(&element->link);
        weston_plane_release(&element->plane);

        if (element->handle != DISPMANX_NO_HANDLE)
                weston_log("ERROR rpi: destroying on-screen element\n");

        pixman_region32_fini(&element->prev_damage);
        rpi_resource_release(&element->resources[0]);
        rpi_resource_release(&element->resources[1]);
        DBG("element %p destroyed (%u)\n", element, element->handle);

        free(element);
}

static void
rpi_element_reuse(struct rpi_element *element)
{
        wl_list_remove(&element->link);
        wl_list_insert(element->output->element_list.prev, &element->link);
}

static void
rpi_element_schedule_destroy(struct rpi_element *element)
{
        wl_list_remove(&element->link);
        wl_list_insert(element->output->old_element_list.prev,
                       &element->link);
}

static int
rpi_element_damage(struct rpi_element *element, struct wl_buffer *buffer,
                   pixman_region32_t *damage)
{
        pixman_region32_t upload;
        int ret;

        if (!pixman_region32_not_empty(damage))
                return 0;

        DBG("element %p update resource %p\n", element, element->back);

        if (element->single_buffer) {
                ret = rpi_resource_update(element->back, buffer, damage);
        } else {
                pixman_region32_init(&upload);
                pixman_region32_union(&upload, &element->prev_damage, damage);
                ret = rpi_resource_update(element->back, buffer, &upload);
                pixman_region32_fini(&upload);
        }

        pixman_region32_copy(&element->prev_damage, damage);
        element->need_swap = 1;

        return ret;
}

static void
rpi_element_compute_rects(struct rpi_element *element,
                          VC_RECT_T *src_rect, VC_RECT_T *dst_rect)
{
        struct weston_output *output = &element->output->base;
        int src_x, src_y;
        int dst_x, dst_y;
        int width, height;

        /* assume element->plane.{x,y} == element->surface->geometry.{x,y} */
        src_x = 0;
        src_y = 0;
        width = element->surface->geometry.width;
        height = element->surface->geometry.height;

        dst_x = element->plane.x - output->x;
        dst_y = element->plane.y - output->y;

        if (dst_x < 0) {
                width += dst_x;
                src_x -= dst_x;
                dst_x = 0;
        }

        if (dst_y < 0) {
                height += dst_y;
                src_y -= dst_y;
                dst_y = 0;
        }

        width = int_max(width, 0);
        height = int_max(height, 0);

        /* src_rect is in 16.16, dst_rect is in 32.0 unsigned fixed point */
        vc_dispmanx_rect_set(src_rect, src_x << 16, src_y << 16,
                             width << 16, height << 16);
        vc_dispmanx_rect_set(dst_rect, dst_x, dst_y, width, height);
}

static void
rpi_element_dmx_add(struct rpi_element *element,
                    DISPMANX_UPDATE_HANDLE_T update, int layer)
{
        VC_DISPMANX_ALPHA_T alphasetup = {
                DISPMANX_FLAGS_ALPHA_FROM_SOURCE | DISPMANX_FLAGS_ALPHA_PREMULT,
                255, /* opacity 0-255 */
                0 /* mask resource handle */
        };
        VC_RECT_T dst_rect;
        VC_RECT_T src_rect;

        rpi_element_compute_rects(element, &src_rect, &dst_rect);

        element->handle = vc_dispmanx_element_add(
                update,
                element->output->display,
                layer,
                &dst_rect,
                element->back->handle,
                &src_rect,
                DISPMANX_PROTECTION_NONE,
                &alphasetup,
                NULL /* clamp */,
                DISPMANX_NO_ROTATE);
        DBG("element %p add %u\n", element, element->handle);
}

static void
rpi_element_dmx_swap(struct rpi_element *element,
                     DISPMANX_UPDATE_HANDLE_T update)
{
        VC_RECT_T rect;
        pixman_box32_t *r;

        /* XXX: skip, iff resource was not reallocated, and single-buffering */
        vc_dispmanx_element_change_source(update, element->handle,
                                          element->back->handle);

        /* This is current damage now, after rpi_assign_plane() */
        r = pixman_region32_extents(&element->prev_damage);

        vc_dispmanx_rect_set(&rect, r->x1, r->y1,
                             r->x2 - r->x1, r->y2 - r->y1);
        vc_dispmanx_element_modified(update, element->handle, &rect);
        DBG("element %p swap\n", element);
}

static void
rpi_element_dmx_move(struct rpi_element *element,
                     DISPMANX_UPDATE_HANDLE_T update, int layer)
{
        VC_RECT_T dst_rect;
        VC_RECT_T src_rect;

        /* XXX: return early, if all attributes stay the same */

        rpi_element_compute_rects(element, &src_rect, &dst_rect);

        vc_dispmanx_element_change_attributes(
                update,
                element->handle,
                ELEMENT_CHANGE_LAYER |
                        ELEMENT_CHANGE_DEST_RECT |
                        ELEMENT_CHANGE_SRC_RECT,
                layer,
                255,
                &dst_rect,
                &src_rect,
                DISPMANX_NO_HANDLE,
                VC_IMAGE_ROT0);
        DBG("element %p move\n", element);
}

static int
rpi_element_update(struct rpi_element *element,
                   DISPMANX_UPDATE_HANDLE_T update, int layer)
{
        struct rpi_resource *tmp;

        if (element->handle == DISPMANX_NO_HANDLE) {
                /* need_swap is already true, see rpi_assign_plane() */

                rpi_element_dmx_add(element, update, layer);
                if (element->handle == DISPMANX_NO_HANDLE)
                        weston_log("ERROR rpi: element_add() failed.\n");
        } else {
                if (element->need_swap)
                        rpi_element_dmx_swap(element, update);
                rpi_element_dmx_move(element, update, layer);
        }
        element->layer = layer;

        if (element->need_swap) {
                tmp = element->front;
                element->front = element->back;
                element->back = tmp;
                element->need_swap = 0;
                DBG("new back %p, new front %p\n",
                    element->back, element->front);
        }

        return 0;
}

static uint64_t
rpi_get_current_time(void)
{
        struct timeval tv;

        /* XXX: use CLOCK_MONOTONIC instead? */
        gettimeofday(&tv, NULL);
        return (uint64_t)tv.tv_sec * 1000 + tv.tv_usec / 1000;
}

static void
rpi_flippipe_update_complete(DISPMANX_UPDATE_HANDLE_T update, void *data)
{
        /* This function runs in a different thread. */
        struct rpi_flippipe *flippipe = data;
        uint64_t time;
        ssize_t ret;

        /* manufacture flip completion timestamp */
        time = rpi_get_current_time();

        ret = write(flippipe->writefd, &time, sizeof time);
        if (ret != sizeof time)
                weston_log("ERROR: %s failed to write, ret %zd, errno %d\n",
                           __func__, ret, errno);
}

static int
rpi_dispmanx_update_submit(DISPMANX_UPDATE_HANDLE_T update,
                           struct rpi_output *output)
{
        /*
         * The callback registered here will eventually be called
         * in a different thread context. Therefore we cannot call
         * the usual functions from rpi_flippipe_update_complete().
         * Instead, we have a pipe for passing the message from the
         * thread, waking up the Weston main event loop, calling
         * rpi_flippipe_handler(), and then ending up in
         * rpi_output_update_complete() in the main thread context,
         * where we can do the frame finishing work.
         */
        return vc_dispmanx_update_submit(update, rpi_flippipe_update_complete,
                                         &output->flippipe);
}

static void
rpi_output_update_complete(struct rpi_output *output, uint64_t time);

static int
rpi_flippipe_handler(int fd, uint32_t mask, void *data)
{
        struct rpi_output *output = data;
        ssize_t ret;
        uint64_t time;

        if (mask != WL_EVENT_READABLE)
                weston_log("ERROR: unexpected mask 0x%x in %s\n",
                           mask, __func__);

        ret = read(fd, &time, sizeof time);
        if (ret != sizeof time) {
                weston_log("ERROR: %s failed to read, ret %zd, errno %d\n",
                           __func__, ret, errno);
        }

        rpi_output_update_complete(output, time);

        return 1;
}

static int
rpi_flippipe_init(struct rpi_flippipe *flippipe, struct rpi_output *output)
{
        struct wl_event_loop *loop;
        int fd[2];

        if (pipe2(fd, O_CLOEXEC) == -1)
                return -1;

        flippipe->readfd = fd[0];
        flippipe->writefd = fd[1];

        loop = wl_display_get_event_loop(output->compositor->base.wl_display);
        flippipe->source = wl_event_loop_add_fd(loop, flippipe->readfd,
                                                WL_EVENT_READABLE,
                                                rpi_flippipe_handler, output);

        if (!flippipe->source) {
                close(flippipe->readfd);
                close(flippipe->writefd);
                return -1;
        }

        return 0;
}

static void
rpi_flippipe_release(struct rpi_flippipe *flippipe)
{
        wl_event_source_remove(flippipe->source);
        close(flippipe->readfd);
        close(flippipe->writefd);
}

static struct rpi_element *
find_rpi_element_from_surface(struct weston_surface *surface)
{
        struct wl_listener *listener;
        struct rpi_element *element;

        listener = wl_signal_get(&surface->resource.destroy_signal,
                                 rpi_element_handle_surface_destroy);
        if (!listener)
                return NULL;

        element = container_of(listener, struct rpi_element,
                               surface_destroy_listener);

        if (element->surface != surface)
                weston_log("ERROR rpi: sanity check failure in %s.\n",
                           __func__);

        return element;
}

static struct rpi_element *
rpi_assign_plane(struct weston_surface *surface, struct rpi_output *output)
{
        struct rpi_element *element;

        /* dispmanx elements cannot transform */
        if (surface->transform.enabled) {
                /* XXX: inspect the transformation matrix, we might still
                 * be able to put it into an element; scaling, additional
                 * translation (window titlebar context menus?)
                 */
                DBG("surface %p rejected: transform\n", surface);
                return NULL;
        }

        /* only shm surfaces supported */
        if (surface->buffer_ref.buffer &&
            !wl_buffer_is_shm(surface->buffer_ref.buffer)) {
                DBG("surface %p rejected: not shm\n", surface);
                return NULL;
        }

        if (surface->buffer_transform != WL_OUTPUT_TRANSFORM_NORMAL) {
                DBG("surface %p rejected: unsupported buffer transform\n",
                    surface);
                return NULL;
        }

        /* check if this surface previously belonged to an element */
        element = find_rpi_element_from_surface(surface);

        if (element) {
                rpi_element_reuse(element);
                element->plane.x = floor(surface->geometry.x);
                element->plane.y = floor(surface->geometry.y);
                DBG("surface %p reuse element %p\n", surface, element);
        } else {
                if (!surface->buffer_ref.buffer) {
                        DBG("surface %p rejected: no buffer\n", surface);
                        return NULL;
                }

                element = rpi_element_create(output, surface);
                DBG("element %p created\n", element);
        }

        if (!element) {
                DBG("surface %p rejected: no element\n", surface);
                return NULL;
        }

        return element;
}

static void
rpi_output_assign_planes(struct weston_output *base)
{
        struct rpi_output *output = to_rpi_output(base);
        struct rpi_compositor *compositor = output->compositor;
        struct weston_surface *surface;
        pixman_region32_t overlap;
        pixman_region32_t surface_overlap;
        struct rpi_element *element;
        int n = 0;

        /* Construct the list of rpi_elements to be used into
         * output->element_list, which is empty right now.
         * Re-used elements are moved from old_element_list to
         * element_list. */

        DBG("%s\n", __func__);

        pixman_region32_init(&overlap);
        wl_list_for_each(surface, &compositor->base.surface_list, link) {
                /* always, since all buffers are shm on rpi */
                surface->keep_buffer = 1;

                pixman_region32_init(&surface_overlap);
                pixman_region32_intersect(&surface_overlap, &overlap,
                                          &surface->transform.boundingbox);

                element = NULL;
                if (!pixman_region32_not_empty(&surface_overlap) &&
                    n < compositor->max_planes)
                        element = rpi_assign_plane(surface, output);

                if (element) {
                        weston_surface_move_to_plane(surface, &element->plane);
                        DBG("surface %p (%dx%d@%.1f,%.1f) to element %p\n",
                            surface,
                            surface->geometry.width, surface->geometry.height,
                            surface->geometry.x, surface->geometry.y, element);

                        /* weston_surface_move_to_plane() does full-surface
                         * damage, if the plane is new, so no need to force
                         * initial resource update.
                         */
                        if (rpi_element_damage(element,
                                               surface->buffer_ref.buffer,
                                               &surface->damage) < 0) {
                                rpi_element_schedule_destroy(element);
                                DBG("surface %p rejected: resource update failed\n",
                                    surface);
                                element = NULL;
                        } else {
                                n++;
                        }
                }

                if (!element) {
                        weston_surface_move_to_plane(surface,
                                        &compositor->base.primary_plane);
                        DBG("surface %p (%dx%d@%.1f,%.1f) to primary plane\n",
                            surface,
                            surface->geometry.width, surface->geometry.height,
                            surface->geometry.x, surface->geometry.y);
                        pixman_region32_union(&overlap, &overlap,
                                              &surface->transform.boundingbox);
                }

                pixman_region32_fini(&surface_overlap);
        }
        pixman_region32_fini(&overlap);
}

static void
rpi_remove_elements(struct wl_list *element_list,
                    DISPMANX_UPDATE_HANDLE_T update)
{
        struct rpi_element *element;

        wl_list_for_each(element, element_list, link) {
                if (element->handle == DISPMANX_NO_HANDLE)
                        continue;

                vc_dispmanx_element_remove(update, element->handle);
                DBG("element %p remove %u\n", element, element->handle);
                element->handle = DISPMANX_NO_HANDLE;
        }
}

static void
rpi_output_destroy_old_elements(struct rpi_output *output)
{
        struct rpi_element *element, *tmp;

        wl_list_for_each_safe(element, tmp, &output->old_element_list, link) {
                if (element->handle != DISPMANX_NO_HANDLE)
                        continue;

                rpi_element_destroy(element);
        }
}

static void
rpi_output_start_repaint_loop(struct weston_output *output)
{
        uint64_t time;

        time = rpi_get_current_time();
        weston_output_finish_frame(output, time);
}

static void
rpi_output_repaint(struct weston_output *base, pixman_region32_t *damage)
{
        struct rpi_output *output = to_rpi_output(base);
        struct rpi_compositor *compositor = output->compositor;
        struct weston_plane *primary_plane = &compositor->base.primary_plane;
        struct rpi_element *element;
        DISPMANX_UPDATE_HANDLE_T update;
        int layer = 10000;

        DBG("frame update start\n");

        /* Update priority higher than in rpi-renderer's
         * output destroy function, see rpi_output_destroy().
         */
        update = vc_dispmanx_update_start(1);

        /* update all live elements */
        wl_list_for_each(element, &output->element_list, link) {
                if (rpi_element_update(element, update, layer--) < 0)
                        weston_log("ERROR rpi: element update failed.\n");
        }

        /* remove all unused elements */
        rpi_remove_elements(&output->old_element_list, update);

        rpi_renderer_set_update_handle(&output->base, update);
        compositor->base.renderer->repaint_output(&output->base, damage);

        pixman_region32_subtract(&primary_plane->damage,
                                 &primary_plane->damage, damage);

        /* schedule callback to rpi_output_update_complete() */
        rpi_dispmanx_update_submit(update, output);
        DBG("frame update submitted\n");

        /* Move the list of elements into the old_element_list. */
        wl_list_insert_list(&output->old_element_list, &output->element_list);
        wl_list_init(&output->element_list);
}

static void
rpi_output_update_complete(struct rpi_output *output, uint64_t time)
{
        DBG("frame update complete(%" PRIu64 ")\n", time);
        rpi_output_destroy_old_elements(output);
        rpi_renderer_finish_frame(&output->base);
        weston_output_finish_frame(&output->base, time);
}

static void
rpi_output_destroy(struct weston_output *base)
{
        struct rpi_output *output = to_rpi_output(base);
        DISPMANX_UPDATE_HANDLE_T update;
        struct rpi_element *element, *tmp;

        DBG("%s\n", __func__);

        update = vc_dispmanx_update_start(0);
        rpi_remove_elements(&output->element_list, update);
        rpi_remove_elements(&output->old_element_list, update);
        vc_dispmanx_update_submit_sync(update);

        rpi_renderer_output_destroy(base);

        wl_list_for_each_safe(element, tmp, &output->element_list, link)
                rpi_element_destroy(element);

        wl_list_for_each_safe(element, tmp, &output->old_element_list, link)
                rpi_element_destroy(element);

        /* rpi_renderer_output_destroy() will schedule a removal of
         * all Dispmanx Elements, and wait for the update to complete.
         * Assuming updates are sequential, the wait should guarantee,
         * that any pending rpi_flippipe_update_complete() callbacks
         * have happened already. Therefore we can destroy the flippipe
         * now.
         */
        rpi_flippipe_release(&output->flippipe);

        wl_list_remove(&output->base.link);
        weston_output_destroy(&output->base);

        vc_dispmanx_display_close(output->display);

        free(output);
}

static const char *transform_names[] = {
        [WL_OUTPUT_TRANSFORM_NORMAL] = "normal",
        [WL_OUTPUT_TRANSFORM_90] = "90",
        [WL_OUTPUT_TRANSFORM_180] = "180",
        [WL_OUTPUT_TRANSFORM_270] = "270",
        [WL_OUTPUT_TRANSFORM_FLIPPED] = "flipped",
        [WL_OUTPUT_TRANSFORM_FLIPPED_90] = "flipped-90",
        [WL_OUTPUT_TRANSFORM_FLIPPED_180] = "flipped-180",
        [WL_OUTPUT_TRANSFORM_FLIPPED_270] = "flipped-270",
};

static int
str2transform(const char *name)
{
        unsigned i;

        for (i = 0; i < ARRAY_LENGTH(transform_names); i++)
                if (strcmp(name, transform_names[i]) == 0)
                        return i;

        return -1;
}

static const char *
transform2str(uint32_t output_transform)
{
        if (output_transform >= ARRAY_LENGTH(transform_names))
                return "<illegal value>";

        return transform_names[output_transform];
}

static int
rpi_output_create(struct rpi_compositor *compositor, uint32_t transform)
{
        struct rpi_output *output;
        DISPMANX_MODEINFO_T modeinfo;
        int ret;
        float mm_width, mm_height;

        output = calloc(1, sizeof *output);
        if (!output)
                return -1;

        output->compositor = compositor;
        output->single_buffer = compositor->single_buffer;
        wl_list_init(&output->element_list);
        wl_list_init(&output->old_element_list);

        if (rpi_flippipe_init(&output->flippipe, output) < 0) {
                weston_log("Creating message pipe failed.\n");
                goto out_free;
        }

        output->display = vc_dispmanx_display_open(DISPMANX_ID_HDMI);
        if (!output->display) {
                weston_log("Failed to open dispmanx HDMI display.\n");
                goto out_pipe;
        }

        ret = vc_dispmanx_display_get_info(output->display, &modeinfo);
        if (ret < 0) {
                weston_log("Failed to get display mode information.\n");
                goto out_dmx_close;
        }

        output->base.start_repaint_loop = rpi_output_start_repaint_loop;
        output->base.repaint = rpi_output_repaint;
        output->base.destroy = rpi_output_destroy;
        output->base.assign_planes = NULL;
        output->base.set_backlight = NULL;
        output->base.set_dpms = NULL;
        output->base.switch_mode = NULL;

        /* XXX: use tvservice to get information from and control the
         * HDMI and SDTV outputs. See:
         * /opt/vc/include/interface/vmcs_host/vc_tvservice.h
         */

        /* only one static mode in list */
        output->mode.flags =
                WL_OUTPUT_MODE_CURRENT | WL_OUTPUT_MODE_PREFERRED;
        output->mode.width = modeinfo.width;
        output->mode.height = modeinfo.height;
        output->mode.refresh = 60000;
        wl_list_init(&output->base.mode_list);
        wl_list_insert(&output->base.mode_list, &output->mode.link);

        output->base.current = &output->mode;
        output->base.origin = &output->mode;
        output->base.subpixel = WL_OUTPUT_SUBPIXEL_UNKNOWN;
        output->base.make = "unknown";
        output->base.model = "unknown";

        /* guess 96 dpi */
        mm_width  = modeinfo.width * (25.4f / 96.0f);
        mm_height = modeinfo.height * (25.4f / 96.0f);

        weston_output_init(&output->base, &compositor->base,
                           0, 0, round(mm_width), round(mm_height),
                           transform, 1);

        if (rpi_renderer_output_create(&output->base, output->display) < 0)
                goto out_output;

        wl_list_insert(compositor->base.output_list.prev, &output->base.link);

        weston_log("Raspberry Pi HDMI output %dx%d px\n",
                   output->mode.width, output->mode.height);
        weston_log_continue(STAMP_SPACE "guessing %d Hz and 96 dpi\n",
                            output->mode.refresh / 1000);
        weston_log_continue(STAMP_SPACE "orientation: %s\n",
                            transform2str(output->base.transform));

        if (!strncmp(transform2str(output->base.transform), "flipped", 7))
                weston_log("warning: flipped output transforms may not work\n");

        return 0;

out_output:
        weston_output_destroy(&output->base);

out_dmx_close:
        vc_dispmanx_display_close(output->display);

out_pipe:
        rpi_flippipe_release(&output->flippipe);

out_free:
        free(output);
        return -1;
}

static void
rpi_led_update(struct weston_seat *seat_base, enum weston_led leds)
{
        struct rpi_seat *seat = to_rpi_seat(seat_base);
        struct evdev_device *device;

        wl_list_for_each(device, &seat->devices_list, link)
                evdev_led_update(device, leds);
}

static const char default_seat[] = "seat0";

static void
device_added(struct udev_device *udev_device, struct rpi_seat *master)
{
        struct evdev_device *device;
        const char *devnode;
        const char *device_seat;
        int fd;

        device_seat = udev_device_get_property_value(udev_device, "ID_SEAT");
        if (!device_seat)
                device_seat = default_seat;

        if (strcmp(device_seat, master->seat_id))
                return;

        devnode = udev_device_get_devnode(udev_device);

        /* Use non-blocking mode so that we can loop on read on
         * evdev_device_data() until all events on the fd are
         * read.  mtdev_get() also expects this. */
        fd = open(devnode, O_RDWR | O_NONBLOCK | O_CLOEXEC);
        if (fd < 0) {
                weston_log("opening input device '%s' failed.\n", devnode);
                return;
        }

        device = evdev_device_create(&master->base, devnode, fd);
        if (!device) {
                close(fd);
                weston_log("not using input device '%s'.\n", devnode);
                return;
        }

        wl_list_insert(master->devices_list.prev, &device->link);
}

static void
evdev_add_devices(struct udev *udev, struct weston_seat *seat_base)
{
        struct rpi_seat *seat = to_rpi_seat(seat_base);
        struct udev_enumerate *e;
        struct udev_list_entry *entry;
        struct udev_device *device;
        const char *path, *sysname;

        e = udev_enumerate_new(udev);
        udev_enumerate_add_match_subsystem(e, "input");
        udev_enumerate_scan_devices(e);
        udev_list_entry_foreach(entry, udev_enumerate_get_list_entry(e)) {
                path = udev_list_entry_get_name(entry);
                device = udev_device_new_from_syspath(udev, path);

                sysname = udev_device_get_sysname(device);
                if (strncmp("event", sysname, 5) != 0) {
                        udev_device_unref(device);
                        continue;
                }

                device_added(device, seat);

                udev_device_unref(device);
        }
        udev_enumerate_unref(e);

        evdev_notify_keyboard_focus(&seat->base, &seat->devices_list);

        if (wl_list_empty(&seat->devices_list)) {
                weston_log(
                        "warning: no input devices on entering Weston. "
                        "Possible causes:\n"
                        "\t- no permissions to read /dev/input/event*\n"
                        "\t- seats misconfigured "
                        "(Weston backend option 'seat', "
                        "udev device property ID_SEAT)\n");
        }
}

static int
evdev_udev_handler(int fd, uint32_t mask, void *data)
{
        struct rpi_seat *seat = data;
        struct udev_device *udev_device;
        struct evdev_device *device, *next;
        const char *action;
        const char *devnode;

        udev_device = udev_monitor_receive_device(seat->udev_monitor);
        if (!udev_device)
                return 1;

        action = udev_device_get_action(udev_device);
        if (!action)
                goto out;

        if (strncmp("event", udev_device_get_sysname(udev_device), 5) != 0)
                goto out;

        if (!strcmp(action, "add")) {
                device_added(udev_device, seat);
        }
        else if (!strcmp(action, "remove")) {
                devnode = udev_device_get_devnode(udev_device);
                wl_list_for_each_safe(device, next, &seat->devices_list, link)
                        if (!strcmp(device->devnode, devnode)) {
                                weston_log("input device %s, %s removed\n",
                                           device->devname, device->devnode);
                                evdev_device_destroy(device);
                                break;
                        }
        }

out:
        udev_device_unref(udev_device);

        return 0;
}

static int
evdev_enable_udev_monitor(struct udev *udev, struct weston_seat *seat_base)
{
        struct rpi_seat *master = to_rpi_seat(seat_base);
        struct wl_event_loop *loop;
        struct weston_compositor *c = master->base.compositor;
        int fd;

        master->udev_monitor = udev_monitor_new_from_netlink(udev, "udev");
        if (!master->udev_monitor) {
                weston_log("udev: failed to create the udev monitor\n");
                return 0;
        }

        udev_monitor_filter_add_match_subsystem_devtype(master->udev_monitor,
                        "input", NULL);

        if (udev_monitor_enable_receiving(master->udev_monitor)) {
                weston_log("udev: failed to bind the udev monitor\n");
                udev_monitor_unref(master->udev_monitor);
                return 0;
        }

        loop = wl_display_get_event_loop(c->wl_display);
        fd = udev_monitor_get_fd(master->udev_monitor);
        master->udev_monitor_source =
                wl_event_loop_add_fd(loop, fd, WL_EVENT_READABLE,
                                     evdev_udev_handler, master);
        if (!master->udev_monitor_source) {
                udev_monitor_unref(master->udev_monitor);
                return 0;
        }

        return 1;
}

static void
evdev_disable_udev_monitor(struct weston_seat *seat_base)
{
        struct rpi_seat *seat = to_rpi_seat(seat_base);

        if (!seat->udev_monitor)
                return;

        udev_monitor_unref(seat->udev_monitor);
        seat->udev_monitor = NULL;
        wl_event_source_remove(seat->udev_monitor_source);
        seat->udev_monitor_source = NULL;
}

static void
evdev_input_create(struct weston_compositor *c, struct udev *udev,
                   const char *seat_id)
{
        struct rpi_seat *seat;

        seat = malloc(sizeof *seat);
        if (seat == NULL)
                return;

        memset(seat, 0, sizeof *seat);
        weston_seat_init(&seat->base, c);
        seat->base.led_update = rpi_led_update;

        wl_list_init(&seat->devices_list);
        seat->seat_id = strdup(seat_id);
        if (!evdev_enable_udev_monitor(udev, &seat->base)) {
                free(seat->seat_id);
                free(seat);
                return;
        }

        evdev_add_devices(udev, &seat->base);
}

static void
evdev_remove_devices(struct weston_seat *seat_base)
{
        struct rpi_seat *seat = to_rpi_seat(seat_base);
        struct evdev_device *device, *next;

        wl_list_for_each_safe(device, next, &seat->devices_list, link)
                evdev_device_destroy(device);

        if (seat->base.keyboard)
                notify_keyboard_focus_out(&seat->base);
}

static void
evdev_input_destroy(struct weston_seat *seat_base)
{
        struct rpi_seat *seat = to_rpi_seat(seat_base);

        evdev_remove_devices(seat_base);
        evdev_disable_udev_monitor(&seat->base);

        weston_seat_release(seat_base);
        free(seat->seat_id);
        free(seat);
}

static void
rpi_compositor_destroy(struct weston_compositor *base)
{
        struct rpi_compositor *compositor = to_rpi_compositor(base);
        struct weston_seat *seat, *next;

        wl_list_for_each_safe(seat, next, &compositor->base.seat_list, link)
                evdev_input_destroy(seat);

        /* destroys outputs, too */
        weston_compositor_shutdown(&compositor->base);

        compositor->base.renderer->destroy(&compositor->base);
        tty_destroy(compositor->tty);

        bcm_host_deinit();
        free(compositor);
}

static void
vt_func(struct weston_compositor *base, int event)
{
        struct rpi_compositor *compositor = to_rpi_compositor(base);
        struct weston_seat *seat;
        struct weston_output *output;

        switch (event) {
        case TTY_ENTER_VT:
                weston_log("entering VT\n");
                compositor->base.focus = 1;
                compositor->base.state = compositor->prev_state;
                weston_compositor_damage_all(&compositor->base);
                wl_list_for_each(seat, &compositor->base.seat_list, link) {
                        evdev_add_devices(compositor->udev, seat);
                        evdev_enable_udev_monitor(compositor->udev, seat);
                }
                break;
        case TTY_LEAVE_VT:
                weston_log("leaving VT\n");
                wl_list_for_each(seat, &compositor->base.seat_list, link) {
                        evdev_disable_udev_monitor(seat);
                        evdev_remove_devices(seat);
                }

                compositor->base.focus = 0;
                compositor->prev_state = compositor->base.state;
                weston_compositor_offscreen(&compositor->base);

                /* If we have a repaint scheduled (either from a
                 * pending pageflip or the idle handler), make sure we
                 * cancel that so we don't try to pageflip when we're
                 * vt switched away.  The OFFSCREEN state will prevent
                 * further attemps at repainting.  When we switch
                 * back, we schedule a repaint, which will process
                 * pending frame callbacks. */

                wl_list_for_each(output,
                                 &compositor->base.output_list, link) {
                        output->repaint_needed = 0;
                }

                break;
        };
}

static void
rpi_restore(struct weston_compositor *base)
{
        struct rpi_compositor *compositor = to_rpi_compositor(base);

        tty_reset(compositor->tty);
}

static void
switch_vt_binding(struct weston_seat *seat, uint32_t time, uint32_t key, void *data)
{
        struct rpi_compositor *ec = data;

        tty_activate_vt(ec->tty, key - KEY_F1 + 1);
}

struct rpi_parameters {
        int tty;
        int max_planes;
        struct rpi_renderer_parameters renderer;
        uint32_t output_transform;
};

static struct weston_compositor *
rpi_compositor_create(struct wl_display *display, int *argc, char *argv[],
                      int config_fd, struct rpi_parameters *param)
{
        struct rpi_compositor *compositor;
        const char *seat = default_seat;
        uint32_t key;

        weston_log("initializing Raspberry Pi backend\n");

        compositor = calloc(1, sizeof *compositor);
        if (compositor == NULL)
                return NULL;

        if (weston_compositor_init(&compositor->base, display, argc, argv,
                                   config_fd) < 0)
                goto out_free;

        compositor->udev = udev_new();
        if (compositor->udev == NULL) {
                weston_log("Failed to initialize udev context.\n");
                goto out_compositor;
        }

        compositor->tty = tty_create(&compositor->base, vt_func, param->tty);
        if (!compositor->tty) {
                weston_log("Failed to initialize tty.\n");
                goto out_udev;
        }

        compositor->base.destroy = rpi_compositor_destroy;
        compositor->base.restore = rpi_restore;

        compositor->base.focus = 1;
        compositor->prev_state = WESTON_COMPOSITOR_ACTIVE;
        compositor->max_planes = int_max(param->max_planes, 0);
        compositor->single_buffer = param->renderer.single_buffer;

        weston_log("Maximum number of additional Dispmanx planes: %d\n",
                   compositor->max_planes);
        weston_log("Dispmanx planes are %s buffered.\n",
                   compositor->single_buffer ? "single" : "double");

        for (key = KEY_F1; key < KEY_F9; key++)
                weston_compositor_add_key_binding(&compositor->base, key,
                                                  MODIFIER_CTRL | MODIFIER_ALT,
                                                  switch_vt_binding, compositor);

        /*
         * bcm_host_init() creates threads.
         * Therefore we must have all signal handlers set and signals blocked
         * before calling it. Otherwise the signals may end in the bcm
         * threads and cause the default behaviour there. For instance,
         * SIGUSR1 used for VT switching caused Weston to terminate there.
         */
        bcm_host_init();

        if (rpi_renderer_create(&compositor->base, &param->renderer) < 0)
                goto out_tty;

        if (rpi_output_create(compositor, param->output_transform) < 0)
                goto out_renderer;

        evdev_input_create(&compositor->base, compositor->udev, seat);

        return &compositor->base;

out_renderer:
        compositor->base.renderer->destroy(&compositor->base);

out_tty:
        tty_destroy(compositor->tty);

out_udev:
        udev_unref(compositor->udev);

out_compositor:
        weston_compositor_shutdown(&compositor->base);

out_free:
        bcm_host_deinit();
        free(compositor);

        return NULL;
}

/*
 * If you have a recent enough firmware in Raspberry Pi, that
 * supports falling back to off-line hardware compositing, and
 * you have enabled it with dispmanx_offline=1 in /boot/config.txt,
 * then VideoCore should be able to handle almost 100 Dispmanx
 * elements. Therefore use 80 as the default limit.
 *
 * If you don't have off-line compositing support, this would be
 * better as something like 10. Failing on-line compositing may
 * show up as visible glitches, HDMI blanking, or invisible surfaces.
 *
 * When the max-planes number is reached, rpi-backend will start
 * to fall back to GLESv2 compositing.
 */
#define DEFAULT_MAX_PLANES 80

WL_EXPORT struct weston_compositor *
backend_init(struct wl_display *display, int *argc, char *argv[],
             int config_fd)
{
        const char *transform = "normal";
        int ret;

        struct rpi_parameters param = {
                .tty = 0, /* default to current tty */
                .max_planes = DEFAULT_MAX_PLANES,
                .renderer.single_buffer = 0,
                .output_transform = WL_OUTPUT_TRANSFORM_NORMAL,
        };

        const struct weston_option rpi_options[] = {
                { WESTON_OPTION_INTEGER, "tty", 0, &param.tty },
                { WESTON_OPTION_INTEGER, "max-planes", 0, &param.max_planes },
                { WESTON_OPTION_BOOLEAN, "single-buffer", 0,
                  &param.renderer.single_buffer },
                { WESTON_OPTION_STRING, "transform", 0, &transform },
        };

        parse_options(rpi_options, ARRAY_LENGTH(rpi_options), argc, argv);

        ret = str2transform(transform);
        if (ret < 0)
                weston_log("invalid transform \"%s\"\n", transform);
        else
                param.output_transform = ret;

        return rpi_compositor_create(display, argc, argv, config_fd, &param);
}