The attached patch puts a hard 32k ceiling on copies to and from
the VGA VRAM space.
This bug was discovered with a 1920x1440 framebuffer console - before
switching from VGA, the console is expanded to 240 cols x 90 rows, equaling
a screenbuf_size of 43200 bytes. Since the VGA VRAM space is only 32k bytes
big, calling vgacon_save_screen during the console transfer copied in a good
chunk of the video BIOS living at 0xc0000 too, resulting in some very purty
colors and characters at the bottom of the new console.
Senior Linux Engineer
AMD - Personal Connectivity Solutions Group