ui: simplify gl unblock & flush

GraphicHw.gl_flushed was introduced to notify the
device (vhost-user-gpu) that the GL resources (the display scanout) are
no longer needed.

It was decoupled from QEMU own gl-blocking mechanism, but that
difference isn't helping. Instead, we can reuse QEMU gl-blocking and
notify virtio_gpu_gl_flushed() when unblocking (to unlock
vhost-user-gpu).

An extra block/unblock is added arount dpy_gl_update() so existing
backends that don't block will have the flush event handled. It will
also help when there are no backends associated.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

hw/display/vhost-user-gpu.c

@@ -254,8 +254,8 @@ vhost_user_gpu_handle_display(VhostUserGPU *g, VhostUserGpuMsg *msg)
             vhost_user_gpu_unblock(g);
             break;
         }
-        dpy_gl_update(con, m->x, m->y, m->width, m->height);
         g->backend_blocked = true;
+        dpy_gl_update(con, m->x, m->y, m->width, m->height);
         break;
     }
     case VHOST_USER_GPU_UPDATE: {

hw/display/virtio-gpu-base.c

@@ -117,6 +117,10 @@ virtio_gpu_gl_block(void *opaque, bool block)
         g->renderer_blocked--;
     }
     assert(g->renderer_blocked >= 0);
+
+    if (!block && g->renderer_blocked == 0) {
+        virtio_gpu_gl_flushed(g);
+    }
 }
 
 static int
@@ -143,7 +147,6 @@ static const GraphicHwOps virtio_gpu_ops = {
     .text_update = virtio_gpu_text_update,
     .ui_info = virtio_gpu_ui_info,
     .gl_block = virtio_gpu_gl_block,
-    .gl_flushed = virtio_gpu_gl_flushed,
 };
 
 bool

hw/display/virtio-vga.c

@@ -68,16 +68,6 @@ static void virtio_vga_base_gl_block(void *opaque, bool block)
     }
 }
 
-static void virtio_vga_base_gl_flushed(void *opaque)
-{
-    VirtIOVGABase *vvga = opaque;
-    VirtIOGPUBase *g = vvga->vgpu;
-
-    if (g->hw_ops->gl_flushed) {
-        g->hw_ops->gl_flushed(g);
-    }
-}
-
 static int virtio_vga_base_get_flags(void *opaque)
 {
     VirtIOVGABase *vvga = opaque;
@@ -93,7 +83,6 @@ static const GraphicHwOps virtio_vga_base_ops = {
     .text_update = virtio_vga_base_text_update,
     .ui_info = virtio_vga_base_ui_info,
     .gl_block = virtio_vga_base_gl_block,
-    .gl_flushed = virtio_vga_base_gl_flushed,
 };
 
 static const VMStateDescription vmstate_virtio_vga_base = {

include/ui/console.h

@@ -391,7 +391,6 @@ typedef struct GraphicHwOps {
     void (*update_interval)(void *opaque, uint64_t interval);
     int (*ui_info)(void *opaque, uint32_t head, QemuUIInfo *info);
     void (*gl_block)(void *opaque, bool block);
-    void (*gl_flushed)(void *opaque);
 } GraphicHwOps;
 
 QemuConsole *graphic_console_init(DeviceState *dev, uint32_t head,
@@ -407,7 +406,6 @@ void graphic_hw_update_done(QemuConsole *con);
 void graphic_hw_invalidate(QemuConsole *con);
 void graphic_hw_text_update(QemuConsole *con, console_ch_t *chardata);
 void graphic_hw_gl_block(QemuConsole *con, bool block);
-void graphic_hw_gl_flushed(QemuConsole *con);
 
 void qemu_console_early_init(void);
 

ui/console.c

@@ -267,15 +267,6 @@ void graphic_hw_gl_block(QemuConsole *con, bool block)
     }
 }
 
-void graphic_hw_gl_flushed(QemuConsole *con)
-{
-    assert(con != NULL);
-
-    if (con->hw_ops->gl_flushed) {
-        con->hw_ops->gl_flushed(con->hw);
-    }
-}
-
 int qemu_console_get_window_id(QemuConsole *con)
 {
     return con->window_id;
@@ -1894,7 +1885,10 @@ void dpy_gl_update(QemuConsole *con,
                    uint32_t x, uint32_t y, uint32_t w, uint32_t h)
 {
     assert(con->gl);
+
+    graphic_hw_gl_block(con, true);
     con->gl->ops->dpy_gl_update(con->gl, x, y, w, h);
+    graphic_hw_gl_block(con, false);
 }
 
 /***********************************************************/

ui/gtk-egl.c

@@ -119,8 +119,6 @@ void gd_egl_draw(VirtualConsole *vc)
 
         glFlush();
     }
-
-    graphic_hw_gl_flushed(vc->gfx.dcl.con);
 }
 
 void gd_egl_update(DisplayChangeListener *dcl,

ui/gtk-gl-area.c

@@ -101,8 +101,6 @@ void gd_gl_area_draw(VirtualConsole *vc)
         surface_gl_setup_viewport(vc->gfx.gls, vc->gfx.ds, ww, wh);
         surface_gl_render_texture(vc->gfx.gls, vc->gfx.ds);
     }
-
-    graphic_hw_gl_flushed(vc->gfx.dcl.con);
 }
 
 void gd_gl_area_update(DisplayChangeListener *dcl,

ui/gtk.c

@@ -593,7 +593,6 @@ void gd_hw_gl_flushed(void *vcon)
     close(dmabuf->fence_fd);
     dmabuf->fence_fd = -1;
     graphic_hw_gl_block(vc->gfx.dcl.con, false);
-    graphic_hw_gl_flushed(vc->gfx.dcl.con);
 }
 
 /** DisplayState Callbacks (opengl version) **/

ui/sdl2-gl.c

@@ -58,7 +58,6 @@ static void sdl2_gl_render_surface(struct sdl2_console *scon)
 
     surface_gl_render_texture(scon->gls, scon->surface);
     SDL_GL_SwapWindow(scon->real_window);
-    graphic_hw_gl_flushed(scon->dcl.con);
 }
 
 void sdl2_gl_update(DisplayChangeListener *dcl,
@@ -241,5 +240,4 @@ void sdl2_gl_scanout_flush(DisplayChangeListener *dcl,
     egl_fb_blit(&scon->win_fb, &scon->guest_fb, !scon->y0_top);
 
     SDL_GL_SwapWindow(scon->real_window);
-    graphic_hw_gl_flushed(dcl->con);
 }

ui/spice-display.c

@@ -830,7 +830,6 @@ static void qemu_spice_gl_unblock_bh(void *opaque)
     SimpleSpiceDisplay *ssd = opaque;
 
     qemu_spice_gl_block(ssd, false);
-    graphic_hw_gl_flushed(ssd->dcl.con);
 }
 
 static void qemu_spice_gl_block_timer(void *opaque)