console: block rendering until client is done

Allow gl user interfaces to block display device gl rendering.
The ui code might want to do that in case it takes a little
longer to bring things to screen, for example because we'll
hand over a dma-buf to another process (spice will do that).
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>

include/ui/console.h

@@ -362,6 +362,7 @@ typedef struct GraphicHwOps {
     void (*text_update)(void *opaque, console_ch_t *text);
     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);
 } GraphicHwOps;
 
 QemuConsole *graphic_console_init(DeviceState *dev, uint32_t head,
@@ -374,6 +375,7 @@ void graphic_console_set_hwops(QemuConsole *con,
 void graphic_hw_update(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);
 
 QemuConsole *qemu_console_lookup_by_index(unsigned int index);
 QemuConsole *qemu_console_lookup_by_device(DeviceState *dev, uint32_t head);

ui/console.c

@@ -261,6 +261,16 @@ void graphic_hw_update(QemuConsole *con)
     }
 }
 
+void graphic_hw_gl_block(QemuConsole *con, bool block)
+{
+    if (!con) {
+        con = active_console;
+    }
+    if (con && con->hw_ops->gl_block) {
+        con->hw_ops->gl_block(con->hw, block);
+    }
+}
+
 void graphic_hw_invalidate(QemuConsole *con)
 {
     if (!con) {