help adding extended text modes in Hypervisor

[Edward Middleton <edward@nikon-sys.co.jp>]

I am trying to get the hypervisor to run in an extended text modes,
specifically 132x44 text mode. I don't really know much about
setting video modes so there may be something inherently broken with
my approach. I have done some Linux device drivers programming and a
little assembler but am probably out of my depth. I have tried
putting the correct VGA register settings (taken after booting into
132x44 text mode vga=0x133 in regular Linux) for this mode into

xen-2.0/xen/drivers/char/console.c
static void init_vga(void)
{
...
static unsigned char regs[]

and setting the #define COLUMNS,LINES

This failed resulted in the monitor switching off at boot, though it
did still boot.

I also looked into using the Linux video initialization routine in
(line 110 linux/arch/i386/boot/video.S). Firstly in
(xen-2.0/xen/arch/x86/boot/x86_32.S) but this doesn't look like the
write place.

I guess video.S corresponds to the init_vga function
(xen-2.0/xen/drivers/char/console.c) the Xen Hypervisor. In (line 398
linux/arch/i386/boot/setup.S) where the video routine is called the
comment states that %ds must be pointing to the bootsector, what is
this for? how would you do this? Near the end setup.S the video.S is
included and at the end a comment "after this point there is some free
space which is used by by the video mode handling code". Is this what
the %ds is being used for?

Any help or advice would be appreciated.

Edward Middleton



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