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

[Jim H. <jim...@ac...>]

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.



-- 
Jim Hague - jim...@in... (Work), ji...@be... (Play)
Never trust a computer you can't lift or you don't control.