Re: [Qemu-devel] [PATCH] Add QEMU DirectFB display driver

[Anthony Liguori <anthony@codemonkey.ws>]

On 05/14/2010 11:58 AM, Julian Pidancet wrote:
> This patch implements a DirectFB driver for QEMU. It allows Qemu to
> draw a VM graphic output directly in the framebuffer of the host,
> without having to rely on X11.
> DirectFB also provides with a generic interface take advantage of graphic
> hardware acceleration for a bunch of different supported cards.
>
> In this driver, the DirectFB library gives Qemu a pointer to mapped
> video memory, which allows Qemu to update the display without extra copy.
> In the case where the guest framebuffer is not compatible with the host
> framebuffer, DirectFB surface blitting functions are used and can be
> accellerated wherever it is possible with the hardware.
>
> DirectFB is a thin library heavily used in embedded or minimal systems
> which don't require X11 overhead. One use case would be to build a
> Xen-based client-class hypervisor, with a minimal dom0 running Qemu as
> device-model. The dom0 could render the domU graphical outputs on the
> physical screen using this patch without having X11 installed.
>
> The other solution would be to use the DirectFB driver for SDL which
> would allow to do slightly the same as this patch. But that would mean
> having to deal with an additional layer in the graphical stack, which is
> not exactly what one wants from a performance or a complexity point of
> view.
> As an example, the SDL library gives no garantee that the surface
> pointer returned by SDL_SetVideoMode(), if called with the
> SDL_HWSURFACE, will be located in video memory [1], especially if the
> SDL main surface is not fullscreen. For this reason, you can never
> assume that SDL will not perform extra copy operations on your behalf
> without notifying you.
>    

But that's a feature.  One would assume that SDL tries to allocate a 
hardware surface whenever it can.

Can you provide some performance data to justify this since SDL provides 
the same ability?

Regards,

Anthony Liguori

> [1] http://www.libsdl.org/cgi/docwiki.cgi/SDL_SetVideoMode
>
> Signed-off-by: Julian Pidancet<julian.pidancet@citrix.com>
> ---
>   Makefile        |    4 +
>   Makefile.objs   |    1 +
>   configure       |   21 +++
>   console.h       |    3 +
>   directfb.c      |  394 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   qemu-options.hx |   10 ++
>   sysemu.h        |    1 +
>   vl.c            |   12 ++
>   8 files changed, 446 insertions(+), 0 deletions(-)
>   create mode 100644 directfb.c
>
> diff --git a/Makefile b/Makefile
> index eb9e02b..6932c81 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -106,6 +106,10 @@ sdl.o: sdl.c keymaps.h sdl_keysym.h sdl_zoom.h
>
>   sdl.o audio/sdlaudio.o sdl_zoom.o baum.o: QEMU_CFLAGS += $(SDL_CFLAGS)
>
> +directfb.o: directfb.c
> +
> +directfb.o: QEMU_CFLAGS += $(DIRECTFB_CFLAGS)
> +
>   acl.o: acl.h acl.c
>
>   vnc.h: vnc-tls.h vnc-auth-vencrypt.h vnc-auth-sasl.h keymaps.h
> diff --git a/Makefile.objs b/Makefile.objs
> index ecdd53e..0904b07 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -102,6 +102,7 @@ common-obj-y += $(addprefix audio/, $(audio-obj-y))
>   common-obj-y += keymaps.o
>   common-obj-$(CONFIG_SDL) += sdl.o sdl_zoom.o x_keymap.o
>   common-obj-$(CONFIG_CURSES) += curses.o
> +common-obj-$(CONFIG_DIRECTFB) += directfb.o
>   common-obj-y += vnc.o acl.o d3des.o
>   common-obj-y += vnc-encoding-zlib.o vnc-encoding-hextile.o
>   common-obj-y += iov.o
> diff --git a/configure b/configure
> index 36d028f..eb73415 100755
> --- a/configure
> +++ b/configure
> @@ -258,6 +258,7 @@ kvm=""
>   kvm_para=""
>   nptl=""
>   sdl=""
> +directfb="no"
>   sparse="no"
>   uuid=""
>   vde=""
> @@ -502,6 +503,10 @@ for opt do
>     ;;
>     --sysconfdir=*) sysconfdir="$optarg"
>     ;;
> +  --disable-directfb) directfb="no"
> +  ;;
> +  --enable-directfb) directfb="yes"
> +  ;;
>     --disable-sdl) sdl="no"
>     ;;
>     --enable-sdl) sdl="yes"
> @@ -763,6 +768,8 @@ echo "  --disable-strip          disable stripping binaries"
>   echo "  --disable-werror         disable compilation abort on warning"
>   echo "  --disable-sdl            disable SDL"
>   echo "  --enable-sdl             enable SDL"
> +echo "  --disable-directfb       disable DirectFB"
> +echo "  --enable-directfb        enable DirectFB"
>   echo "  --enable-cocoa           enable COCOA (Mac OS X only)"
>   echo "  --audio-drv-list=LIST    set audio drivers list:"
>   echo "                           Available drivers: $audio_possible_drivers"
> @@ -1062,6 +1069,15 @@ if test "$sparse" != "no" ; then
>   fi
>
>   ##########################################
> +# DirectFB probe
> +
> +if test "$directfb" = "yes" ; then
> +  directfb_libs=`directfb-config --libs`
> +  directfb_cflags=`directfb-config --cflags`
> +  libs_softmmu="$directfb_libs $libs_softmmu"
> +fi
> +
> +##########################################
>   # SDL probe
>
>   if $pkgconfig sdl --modversion>/dev/null 2>&1; then
> @@ -1999,6 +2015,7 @@ if test "$darwin" = "yes" ; then
>       echo "Cocoa support     $cocoa"
>   fi
>   echo "SDL support       $sdl"
> +echo "DirectFB support  $directfb"
>   echo "curses support    $curses"
>   echo "curl support      $curl"
>   echo "check support     $check_utests"
> @@ -2169,6 +2186,10 @@ fi
>   if test "$cocoa" = "yes" ; then
>     echo "CONFIG_COCOA=y">>  $config_host_mak
>   fi
> +if test "$directfb" = "yes" ; then
> +  echo "CONFIG_DIRECTFB=y">>  $config_host_mak
> +  echo "DIRECTFB_CFLAGS=$directfb_cflags">>  $config_host_mak
> +fi
>   if test "$curses" = "yes" ; then
>     echo "CONFIG_CURSES=y">>  $config_host_mak
>   fi
> diff --git a/console.h b/console.h
> index 6def115..d1dd211 100644
> --- a/console.h
> +++ b/console.h
> @@ -335,6 +335,9 @@ void qemu_console_resize(DisplayState *ds, int width, int height);
>   void qemu_console_copy(DisplayState *ds, int src_x, int src_y,
>                          int dst_x, int dst_y, int w, int h);
>
> +/* directfb.c */
> +void directfb_display_init(DisplayState *ds);
> +
>   /* sdl.c */
>   void sdl_display_init(DisplayState *ds, int full_screen, int no_frame);
>
> diff --git a/directfb.c b/directfb.c
> new file mode 100644
> index 0000000..6dea99a
> --- /dev/null
> +++ b/directfb.c
> @@ -0,0 +1,394 @@
> +/*
> + * QEMU DirectFB display driver
> + *
> + * Copyright (c) 2010 Citrix Systems, Inc.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include<console.h>
> +#include<keymaps.h>
> +
> +#include<directfb.h>
> +
> +static IDirectFB *dfb = NULL;
> +static IDirectFBSurface *primary = NULL;
> +static IDirectFBEventBuffer *events = NULL;
> +static IDirectFBSurface *guest = NULL;
> +
> +static void *screen_data = NULL;
> +static int screen_pitch = 0;
> +static int screen_bpp = 0;
> +static int screen_width  = 0;
> +static int screen_height = 0;
> +static int scaling = 0;
> +
> +#define DIRECTFB_IS_VIDEO_PTR(p) \
> +    (p>= (uint8_t *) screen_data&&  \
> +     p<  (uint8_t *) screen_data + screen_height * screen_pitch)
> +
> +static DFBSurfacePixelFormat directfb_bpp_to_pixelformat(int bpp)
> +{
> +    switch (bpp) {
> +        case 16:
> +            return DSPF_RGB16;
> +        case 24:
> +            return DSPF_RGB24;
> +        case 32:
> +            return DSPF_RGB32;
> +        default:
> +            return DSPF_UNKNOWN;
> +    }
> +}
> +
> +static void directfb_clearscreen(void)
> +{
> +    if (screen_data != NULL) {
> +        /* Surface is locked */
> +        memset(screen_data, 0x0,
> +               screen_pitch * screen_height);
> +    } else {
> +        primary->SetColor(primary, 0x0, 0x0, 0x0, 0x0);
> +        primary->FillRectangle(primary, 0, 0, screen_width, screen_height);
> +    }
> +}
> +
> +static void directfb_update(struct DisplayState *s, int x, int y, int w, int h)
> +{
> +    DFBRegion region = {x, y, x + w, y + h};
> +
> +    if (guest) {
> +        if (scaling) {
> +            primary->StretchBlit(primary, guest, NULL, NULL);
> +        } else {
> +            int xoff = (screen_width - ds_get_width(s)) / 2;
> +            int yoff = (screen_height - ds_get_height(s)) / 2;
> +
> +            primary->Blit(primary, guest, NULL, xoff, yoff);
> +
> +            region.x1 += xoff;
> +            region.y1 += yoff;
> +            region.x2 += xoff;
> +            region.x2 += yoff;
> +        }
> +    }
> +
> +    primary->Flip(primary,&region, DSFLIP_NONE);
> +}
> +
> +static void directfb_setdata(DisplayState *s)
> +{
> +    DFBSurfaceDescription dsc;
> +
> +    if (guest) {
> +        guest->Release(guest);
> +        guest = NULL;
> +    }
> +
> +    dsc.flags = DSDESC_WIDTH | DSDESC_HEIGHT |
> +                DSDESC_PIXELFORMAT | DSDESC_PREALLOCATED;
> +    dsc.width = ds_get_width(s);
> +    dsc.height = ds_get_height(s);
> +    dsc.pixelformat = directfb_bpp_to_pixelformat(ds_get_bits_per_pixel(s));
> +    dsc.preallocated[0].data = ds_get_data(s);
> +    dsc.preallocated[0].pitch = ds_get_linesize(s);
> +
> +    dfb->CreateSurface(dfb,&dsc,&guest);
> +}
> +
> +static void directfb_resize(struct DisplayState *s)
> +{
> +    directfb_clearscreen();
> +
> +    if (scaling || ds_get_bits_per_pixel(s) != screen_bpp ||
> +        ds_get_linesize(s) != screen_pitch ||
> +        !DIRECTFB_IS_VIDEO_PTR(ds_get_data(s))) {
> +
> +        directfb_setdata(s);
> +    } else {
> +        if (guest) {
> +            guest->Release(guest);
> +            guest = NULL;
> +        }
> +    }
> +}
> +
> +static int directfb_buttons_state(DFBInputEvent *ev)
> +{
> +    int buttons = 0;
> +
> +    if (ev->buttons&  DIBM_LEFT) {
> +        buttons |= MOUSE_EVENT_LBUTTON;
> +    }
> +    if (ev->buttons&  DIBM_RIGHT) {
> +        buttons |= MOUSE_EVENT_RBUTTON;
> +    }
> +    if (ev->buttons&  DIBM_MIDDLE) {
> +        buttons |= MOUSE_EVENT_MBUTTON;
> +    }
> +
> +    return buttons;
> +}
> +
> +static void directfb_put_keycode(char keycode, int up)
> +{
> +    int scancode = keycode;
> +
> +    /* Pause/Break */
> +    if (keycode == 119) {
> +	scancode = 0x45;
> +        kbd_put_keycode(0xe1);
> +        kbd_put_keycode(0x1d | up ? 0x80 : 0x0);
> +    } else {
> +        /* grey key */
> +        if (keycode>= 0x60&&  keycode<  0x70) {
> +            const char esc[16] = {0x1c, 0x1d, 0x35, 0x37,
> +                                  0x38, 0x46, 0x47, 0x48,
> +                                  0x49, 0x4b, 0x4d, 0x4f,
> +                                  0x50, 0x51, 0x52, 0x53};
> +            scancode = esc[keycode - 0x60];
> +            kbd_put_keycode(0xe0);
> +
> +            /* PrintScreen */
> +            if (keycode == 99) {
> +                scancode = 0x37;
> +                kbd_put_keycode(0x2a | up ? 0x80 : 0x0);
> +                kbd_put_keycode(0xe0);
> +            }
> +        }
> +    }
> +
> +    kbd_put_keycode(scancode | (up ? 0x80 : 0x0));
> +}
> +
> +static void directfb_toggle_fullscreen(struct DisplayState *ds)
> +{
> +    scaling = !scaling;
> +
> +    vga_hw_invalidate();
> +    vga_hw_update();
> +}
> +
> +static void directfb_refresh(struct DisplayState *s)
> +{
> +    DFBInputEvent ev;
> +
> +    vga_hw_update();
> +
> +    while (events->GetEvent(events, DFB_EVENT(&ev)) == DFB_OK) {
> +        switch (ev.type) {
> +            case DIET_KEYRELEASE:
> +                directfb_put_keycode(ev.key_code, 1);
> +                break;
> +            case DIET_KEYPRESS:
> +                /* Toggle centered/fullscreen */
> +                if ((ev.modifiers&  DIMM_CONTROL)&&
> +                    (ev.modifiers&  DIMM_ALT)&&
> +                    (ev.key_id == DIKI_ENTER)) {
> +                    directfb_toggle_fullscreen(s);
> +                    break;
> +                }
> +                directfb_put_keycode(ev.key_code, 0);
> +                break;
> +            case DIET_BUTTONPRESS:
> +            case DIET_BUTTONRELEASE:
> +            case DIET_AXISMOTION:
> +            {
> +                int buttons = directfb_buttons_state(&ev);
> +                int dx = 0;
> +                int dy = 0;
> +                int dz = 0;
> +
> +                if (ev.type == DIET_AXISMOTION) {
> +                    if (ev.axis == DIAI_X) {
> +                        dx = ev.axisrel;
> +                    }
> +                    if (ev.axis == DIAI_Y) {
> +                        dy = ev.axisrel;
> +                    }
> +                    if (ev.axis == DIAI_Z) {
> +                        dz = ev.axisrel;
> +                    }
> +                }
> +
> +                kbd_mouse_event(dx, dy, dz, buttons);
> +                break;
> +            }
> +            case DIET_UNKNOWN:
> +            default:
> +                break;
> +
> +        }
> +    }
> +}
> +
> +static DisplaySurface* directfb_create_displaysurface(int width, int height)
> +{
> +    DisplaySurface *surface = (DisplaySurface*) qemu_mallocz(sizeof(DisplaySurface));
> +    DFBSurfacePixelFormat spf;
> +    surface->width = width;
> +    surface->height = height;
> +
> +    primary->GetPixelFormat(primary,&spf);
> +
> +    if (scaling) {
> +        int bytes_per_pixel = DFB_BYTES_PER_PIXEL(spf);
> +
> +        if (bytes_per_pixel != 2&&  bytes_per_pixel != 4) {
> +            bytes_per_pixel = 4;
> +        }
> +
> +        surface->pf = qemu_default_pixelformat(8 * bytes_per_pixel);
> +        surface->linesize = width * bytes_per_pixel;
> +
> +        surface->flags = QEMU_ALLOCATED_FLAG;
> +        surface->data = qemu_mallocz(surface->linesize * surface->height);
> +    } else {
> +        primary->Lock(primary, DSLF_READ | DSLF_WRITE,&screen_data,&screen_pitch);
> +        surface->pf = qemu_default_pixelformat(screen_bpp);
> +        surface->flags = QEMU_REALPIXELS_FLAG;
> +        surface->linesize = screen_pitch;
> +        surface->data = screen_data +
> +                        ((screen_height - height) / 2) * screen_pitch +
> +                        ((screen_width - width) / 2) * (screen_bpp / 8);
> +    }
> +
> +    return surface;
> +}
> +
> +static void directfb_free_displaysurface(DisplaySurface *surface)
> +{
> +    if (surface == NULL)
> +        return;
> +
> +    if (surface->flags&  QEMU_ALLOCATED_FLAG) {
> +        qemu_free(surface->data);
> +    } else if (surface->flags&  QEMU_REALPIXELS_FLAG) {
> +        primary->Unlock(primary);
> +        screen_data = NULL;
> +        screen_pitch = 0;
> +    }
> +
> +    surface->data = NULL;
> +
> +    qemu_free(surface);
> +}
> +
> +static DisplaySurface* directfb_resize_displaysurface(DisplaySurface *surface,
> +                                                      int width,
> +                                                      int height)
> +{
> +    directfb_free_displaysurface(surface);
> +    return directfb_create_displaysurface(width, height);
> +}
> +
> +static DFBEnumerationResult directfb_attach_inputdevice(DFBInputDeviceID device_id,
> +                                                        DFBInputDeviceDescription desc,
> +                                                        void *data)
> +{
> +    if (!strcmp(desc.vendor, "Linux")) {
> +        return DFENUM_OK;
> +    }
> +
> +    if (desc.type == DIDID_KEYBOARD || desc.type | DIDTF_MOUSE) {
> +        IDirectFBInputDevice *device;
> +
> +        dfb->GetInputDevice(dfb, device_id,&device);
> +
> +        if (events == NULL) {
> +            device->CreateEventBuffer(device,&events);
> +        } else {
> +            device->AttachEventBuffer(device, events);
> +        }
> +    }
> +
> +    return DFENUM_OK;
> +}
> +
> +void directfb_display_init(DisplayState *ds)
> +{
> +    DisplayChangeListener *dcl;
> +    DisplayAllocator *da;
> +    DFBResult status;
> +    DFBSurfaceDescription dsc;
> +    DFBSurfaceCapabilities caps;
> +    DFBSurfacePixelFormat spf;
> +
> +    /*
> +     * Prevent DirectFB to read qemu command line argument in procfs and
> +     * parse it.
> +     */
> +    char prog_name[] = "qemu";
> +    char *prog_argv[] = {prog_name};
> +    char **dfb_argv = prog_argv;
> +    int dfb_argc = 1;
> +
> +    status = DirectFBInit(&dfb_argc,&dfb_argv);
> +    if (status != DFB_OK) {
> +        fprintf(stderr, "Could not initialize DirectFB(%d) - exiting\n", status);
> +        exit(1);
> +    }
> +
> +    DirectFBCreate(&dfb);
> +    dfb->SetCooperativeLevel(dfb, DFSCL_FULLSCREEN);
> +    dsc.flags = DSDESC_CAPS;
> +    dsc.caps = DSCAPS_PRIMARY | DSCAPS_VIDEOONLY | DSCAPS_SHARED;
> +    status = dfb->CreateSurface(dfb,&dsc,&primary);
> +
> +    if (status != DFB_OK) {
> +        fprintf(stderr, "Could not create DirectFB surface(%d) - exiting\n", status);
> +        exit(1);
> +    }
> +
> +    /* Double check surface capabilities */
> +    primary->GetCapabilities(primary,&caps);
> +    if ((caps&  dsc.caps) != dsc.caps ||
> +        caps&  DSCAPS_FLIPPING || caps&  DSCAPS_INTERLACED ||
> +        caps&  DSCAPS_SYSTEMONLY) {
> +        fprintf(stderr, "Wrong DirectFB surface capabilities - exiting\n");
> +        exit(1);
> +    }
> +
> +    primary->GetSize(primary,&screen_width,&screen_height);
> +    primary->GetPixelFormat(primary,&spf);
> +    screen_bpp = DFB_BITS_PER_PIXEL(spf);
> +
> +    dfb->EnumInputDevices(dfb, directfb_attach_inputdevice, NULL);
> +
> +    fprintf(stderr, "Initialized QEMU DirectFB driver. (%dx%d)\n",
> +            screen_width, screen_height);
> +
> +    dcl = qemu_mallocz(sizeof(DisplayChangeListener));
> +    dcl->dpy_update = directfb_update;
> +    dcl->dpy_resize = directfb_resize;
> +    dcl->dpy_refresh = directfb_refresh;
> +    dcl->dpy_setdata = directfb_setdata;
> +    register_displaychangelistener(ds, dcl);
> +
> +    da = qemu_mallocz(sizeof(DisplayAllocator));
> +    da->create_displaysurface = directfb_create_displaysurface;
> +    da->resize_displaysurface = directfb_resize_displaysurface;
> +    da->free_displaysurface = directfb_free_displaysurface;
> +
> +    directfb_clearscreen();
> +
> +    if (register_displayallocator(ds, da) == da) {
> +        dpy_resize(ds);
> +    }
> +}
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 12f6b51..a4bdfbe 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -608,6 +608,16 @@ QEMU can display the VGA output when in text mode using a
>   curses/ncurses interface.  Nothing is displayed in graphical mode.
>   ETEXI
>
> +#ifdef CONFIG_DIRECTFB
> +DEF("directfb", 0, QEMU_OPTION_directfb,
> +    "-directfb       enable DirectFB\n")
> +#endif
> +STEXI
> +@item -directfb
> +@findex -directfb
> +Enable DirectFB.
> +ETEXI
> +
>   #ifdef CONFIG_SDL
>   DEF("no-frame", 0, QEMU_OPTION_no_frame,
>       "-no-frame       open SDL window without a frame and window decorations\n",
> diff --git a/sysemu.h b/sysemu.h
> index fa921df..a2cd5b0 100644
> --- a/sysemu.h
> +++ b/sysemu.h
> @@ -98,6 +98,7 @@ typedef enum DisplayType
>       DT_CURSES,
>       DT_SDL,
>       DT_VNC,
> +    DT_DIRECTFB,
>       DT_NOGRAPHIC,
>   } DisplayType;
>
> diff --git a/vl.c b/vl.c
> index 85bcc84..e6235fa 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3199,6 +3199,11 @@ int main(int argc, char **argv, char **envp)
>               case QEMU_OPTION_full_screen:
>                   full_screen = 1;
>                   break;
> +#ifdef CONFIG_DIRECTFB
> +            case QEMU_OPTION_directfb:
> +                display_type = DT_DIRECTFB;
> +                break;
> +#endif
>   #ifdef CONFIG_SDL
>               case QEMU_OPTION_no_frame:
>                   no_frame = 1;
> @@ -3765,6 +3770,8 @@ int main(int argc, char **argv, char **envp)
>       if (display_type == DT_DEFAULT) {
>   #if defined(CONFIG_SDL) || defined(CONFIG_COCOA)
>           display_type = DT_SDL;
> +#elif defined(CONFIG_DIRECTFB)
> +        display_type = DT_DIRECTFB;
>   #else
>           display_type = DT_VNC;
>           vnc_display = "localhost:0,to=99";
> @@ -3781,6 +3788,11 @@ int main(int argc, char **argv, char **envp)
>           curses_display_init(ds, full_screen);
>           break;
>   #endif
> +#if defined(CONFIG_DIRECTFB)
> +    case DT_DIRECTFB:
> +        directfb_display_init(ds);
> +        break;
> +#endif
>   #if defined(CONFIG_SDL)
>       case DT_SDL:
>           sdl_display_init(ds, full_screen, no_frame);
>