Re: [Linux-fbdev-devel] FB console clears with large white area at startup

[James S. <jsi...@tr...>]

> I've been using the Permedia2 driver on x86 for some time. I've always built
> the kernel with the VGA console and the pm2 driver built in.
> 
> So booting begins through the VGA console, and when the pm2 driver is loaded it
> grabs the console, up goes Tux and on we go. As you might expect.
> Except what actually happens is that most of the screen is cleared to white,
> and console messages appear on the bottom line of the white area. As the
> console scrolls the white area scrolls up the screen, though that part of it to
> the right of Tux remains as long as Tux remains.
> 
> The size of the white area is the size of the VGA screen, both considered in
> terms of character positions. So with regular VGA it is 80x25. I tend to use
> 80x50 VGA, hence 'most' of the screen, my fb console size being 144x56.
> 
> For ages I thought this was a problem with the Permedia2 driver, and so have
> been giving myself an introduction to the console code digging around trying to
> find the problem. I haven't got to the bottom of it, but it looks to me like
> the problem is not a Permedia2 driver one, and that users of other drivers
> should see it to.
> 
> Is this true? Is this an old chestnut that is well understood and has been done
> to death on the list in the past?
> 
> As far as I can tell at the moment, in take_over_console the outgoing console
> is suppose to save its screen contents (if visible) and these will be put onto
> the new console when update_screen() is called. Dumping the saved VGA screen,
> it seems that the saved screen consists entirely of 0x720, which I think
> explains the white. Why the VGA screen contents are like that I have, as yet, no
> idea.

I figured the problem was with the core console code. You found the bug
that I have seen before in other drivers. Dave Jones reported to me for
the 3dfx driver. I never had this problem but he did. Now we know what
causes it. I to have no idea why the VGA screen contents are like that
either.