Re: [Qemu-devel] [PATCH]Fix for minor video corruption under Windows

[Leonardo E. Reiter]

Donald...

thanks... I actually posted a patch to fix this sometime ago, but your 
patch seems more thorough and probably more correct.  Just FYI, I 
attached my patch again.  I will test your patch as well.

Thanks again,

Leo Reiter

Donald D. Dugger wrote:
> If you change the video resolution while running a Windows XP image such that
> it uses fewer bytes of VRAM (either by using fewer bytes per pixel or by
> lowering the resolution) then some window backgrounds will become corrupted.
> This happens because the Windows XP Cirrus Logic driver assumes that VRAM is
> initialized to 0xff whenever the video mode switches between VGA and SVGA.
>
> This patch fixes this problem by resetting VRAM whenever a VGA/SVGA mode switch
> occurs.
>
> Signed-off-by: address@hidden

--
Leonardo E. Reiter
Vice President of Product Development, CTO

Win4Lin, Inc.
Virtual Computing that means Business
Main: +1 512 339 7979
Fax: +1 512 532 6501
http://www.win4lin.com

Index: hw/vga.c
===================================================================
RCS file: /cvsroot/qemu/qemu/hw/vga.c,v
retrieving revision 1.42
diff -a -u -r1.42 vga.c
--- hw/vga.c    9 Apr 2006 01:06:34 -0000       1.42
+++ hw/vga.c    12 Apr 2006 14:53:06 -0000
@@ -1366,6 +1366,8 @@
 
     if (disp_width != s->last_width ||
         height != s->last_height) {
+        if (cirrus_vga_enabled && s->get_bpp(s) >= 8)
+            memset(s->vram_ptr, 0xff, s->vram_size);
         dpy_resize(s->ds, disp_width, height);
         s->last_scr_width = disp_width;
         s->last_scr_height = height;