[Qemu-devel] [PATCH v2 2/2] warn about two vga cards

[Gerd Hoffmann <kraxel@redhat.com>]

Two vga cards will try to register for the same legacy (isa) ioports.
Due to this conflict only one of the two cards will work correctly in
vga mode.

Print a warning message in that case.  Also try registering the ports
only once, so the first vga added to the system will work properly.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/display/vga.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/hw/display/vga.c b/hw/display/vga.c
index c82e6d240a..e811571624 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -2273,6 +2273,7 @@ MemoryRegion *vga_init_io(VGACommonState *s, Object *obj,
 void vga_init(VGACommonState *s, Object *obj, MemoryRegion *address_space,
               MemoryRegion *address_space_io, bool init_vga_ports)
 {
+    static bool vgaports_registered;
     MemoryRegion *vga_io_memory;
     const MemoryRegionPortio *vga_ports, *vbe_ports;
 
@@ -2289,9 +2290,14 @@ void vga_init(VGACommonState *s, Object *obj, MemoryRegion *address_space,
                                         1);
     memory_region_set_coalescing(vga_io_memory);
     if (init_vga_ports) {
-        portio_list_init(&s->vga_port_list, obj, vga_ports, s, "vga");
-        portio_list_set_flush_coalesced(&s->vga_port_list);
-        portio_list_add(&s->vga_port_list, address_space_io, 0x3b0);
+        if (vgaports_registered) {
+            warn_report("multiple vga cards may not work as expected");
+        } else {
+            portio_list_init(&s->vga_port_list, obj, vga_ports, s, "vga");
+            portio_list_set_flush_coalesced(&s->vga_port_list);
+            portio_list_add(&s->vga_port_list, address_space_io, 0x3b0);
+            vgaports_registered = true;
+        }
     }
     if (vbe_ports) {
         portio_list_init(&s->vbe_port_list, obj, vbe_ports, s, "vbe");
-- 
2.9.3