fix screendump

Commit 45efb16124 optimized a bit too
much.  We can skip the vga_invalidate_display() in case no console
switch happened because we don't need a full redraw then.  We can *not*
skip vga_hw_update() though, because the screen content will be stale
then in case nobody else calls vga_hw_update().

Trigger: vga textmode with vnc display and no client connected.

Reported-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Alon Levy <alevy@redhat.com>
Tested-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

hw/blizzard.c

@@ -937,9 +937,7 @@ static void blizzard_screen_dump(void *opaque, const char *filename,
 {
     BlizzardState *s = (BlizzardState *) opaque;
 
-    if (cswitch) {
-        blizzard_update_display(opaque);
-    }
+    blizzard_update_display(opaque);
     if (s && ds_get_data(s->state))
         ppm_save(filename, s->state->surface);
 }

hw/omap_lcdc.c

@@ -267,9 +267,8 @@ static int ppm_save(const char *filename, uint8_t *data,
 static void omap_screen_dump(void *opaque, const char *filename, bool cswitch)
 {
     struct omap_lcd_panel_s *omap_lcd = opaque;
-    if (cswitch) {
-        omap_update_display(opaque);
-    }
+
+    omap_update_display(opaque);
     if (omap_lcd && ds_get_data(omap_lcd->state))
         ppm_save(filename, ds_get_data(omap_lcd->state),
                 omap_lcd->width, omap_lcd->height,

hw/vga.c

@@ -2415,7 +2415,7 @@ static void vga_screen_dump(void *opaque, const char *filename, bool cswitch)
 
     if (cswitch) {
         vga_invalidate_display(s);
-        vga_hw_update();
     }
+    vga_hw_update();
     ppm_save(filename, s->ds->surface);
 }