vnc update fix

We need to remember has_updates for each vnc client.  Otherwise it might
happen that vnc_update_client(has_dirty=1) takes the first exit due to
output buffers not being flushed yet and subsequent calls with
has_dirty=0 take the second exit, wrongly assuming there is nothing to
do because the work defered in the first call is ignored.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NPeter Lieven <pl@kamp.de>

ui/vnc.c

@@ -887,6 +887,7 @@ static int find_and_clear_dirty_height(struct VncState *vs,
 
 static int vnc_update_client(VncState *vs, int has_dirty, bool sync)
 {
+    vs->has_dirty += has_dirty;
     if (vs->need_update && vs->csock != -1) {
         VncDisplay *vd = vs->vd;
         VncJob *job;
@@ -898,7 +899,7 @@ static int vnc_update_client(VncState *vs, int has_dirty, bool sync)
             /* kernel send buffers are full -> drop frames to throttle */
             return 0;
 
-        if (!has_dirty && !vs->audio_cap && !vs->force_update)
+        if (!vs->has_dirty && !vs->audio_cap && !vs->force_update)
             return 0;
 
         /*
@@ -941,6 +942,7 @@ static int vnc_update_client(VncState *vs, int has_dirty, bool sync)
             vnc_jobs_join(vs);
         }
         vs->force_update = 0;
+        vs->has_dirty = 0;
         return n;
     }
 

ui/vnc.h

@@ -263,6 +263,7 @@ struct VncState
     VncDisplay *vd;
     int need_update;
     int force_update;
+    int has_dirty;
     uint32_t features;
     int absolute;
     int last_x;