[Qemu-devel] [RFC] reduce reported VGA framebuffer to 8 MiB

[Alon Levy <alevy@redhat.com>]

Without this windows xp guests set a 4 bits per pixel graphics mode.

With it we get the same behavior as with -vga std, that is a 32 bpp
graphics mode. This fits the size reported by hw/vga-pci.c .
---
Sending as RFC since I'm not sure if this is the right thing, nor that
it doesn't actually interfere with anything else. I did however do the testing
with and without mentioned in the patch comment and code comment.
---
 hw/qxl.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/hw/qxl.c b/hw/qxl.c
index 9a0f588..f6ff9f2 100644
--- a/hw/qxl.c
+++ b/hw/qxl.c
@@ -1332,7 +1332,14 @@ static int qxl_init_primary(PCIDevice *dev)
     if (ram_size < 32 * 1024 * 1024) {
         ram_size = 32 * 1024 * 1024;
     }
-    vga_common_init(vga, ram_size);
+    /*
+     * windows xp guests don't like larger then VGA_RAM_SIZE (8 MiB),
+     * wrongly setting the display to 4 bit color depth. This fix doesn't
+     * affect native mode, where we have modes that require larger amounts
+     * of ram. (The maximum that VBE reports is 1600x1200 32 bit color depth
+     * which fits)
+     */
+    vga_common_init(vga, VGA_RAM_SIZE);
     vga_init(vga);
     register_ioport_write(0x3c0, 16, 1, qxl_vga_ioport_write, vga);
     register_ioport_write(0x3b4,  2, 1, qxl_vga_ioport_write, vga);
-- 
1.7.5.1