On Fri, 18 Jun 2004, John Zielinski wrote:

Geert Uytterhoeven wrote:

quoted

Solution: before initializing and switching to a fbdev, save the contents of
the VGA text memory to the `shadow screen', so the fbdev can clear the frame
buffer memory, and fbcon can recover the current VC contents.

However, it makes things more complex and adds a vgacon dependency to some
code, since you want it to behave differently if people don't compile in
vgacon.

That was the old solution.  I found the root cause of the problem.
There is no code in the vt subsystem to prevent output going to a
console driver after it has been deinitialized.  The vga console does
save the VGA memory to it's shadow screen when it's deinitialized but
any printk's after that screw things up as it starts to output again to
the screen.  Now the shadow screen and the real screen doesn't match
anymore.

Hence vgacon should be replaced by dummycon when it's deinitialized.

quoted

Final solution: VGA is obsolete ;-)

I wish.  Hopefully the new EFI firmware on x86 platforms will initialize
the video card into it's native graphics configuration so we can start
dropping this excess VGA baggage we've been carrying for the last
several years.  Of course there's always linuxbios as well.  :)  What's
the story with VGA on other platforms?

(According to what I learned from the EFI talk at OLS last year) It's worse:
you have to talk to the EFI bytecode to draw text on UGA, no direct access to
the frame buffer ;-(

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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