Comment 3 for bug 1784900

This patch here fixes the issue, but is likely introducing inefficiency. There are two if statements above the patch that should set full_update = 1 due to 'some change', but none of them triggers it. So I think the surface is wrong and needs to be recreated.

diff --git a/hw/display/vga.c b/hw/display/vga.c
index ed476e4e80..71b5684994 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -1571,6 +1571,7 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
          * must be updated with the new base address */
         full_update = 1;
     }
+ full_update = 1;

     if (full_update) {
         if (share_surface) {

A better solution may be this one here:

diff --git a/hw/display/vga.c b/hw/display/vga.c
index ed476e4e80..4f365b6d43 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -1566,7 +1566,7 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
         full_update = 1;
     }
     if (surface_data(surface) != s->vram_ptr + (s->start_addr * 4)
- && is_buffer_shared(surface)) {
+ /*&& is_buffer_shared(surface)*/) {
         /* base address changed (page flip) -> shared display surfaces
          * must be updated with the new base address */
         full_update = 1;