Re: [PATCH] vgacon: Workaround for resize bug in some chipsets

[Martin Mares <mj@ucw.cz>]

Hello!

> Reported from Redhat Bugzilla Bug 170450
> 
> "I updated to the development kernel and now during boot only the top of the
> text is visable. For example the monitor screen the is the lines and I can
> only  see text in the asterik area.
> ---------------------
> | ****************  |
> | *              *  |
> | *              *  |
> | ****************  |
> |                   |
> |                   |
> |                   |
> ---------------------
> 
> I have a Silicon Graphics 1600sw LCD panel with a Number Nine Revolution 4
> video card."
> 
> This bug seems to be a glitch in the VGA core of this chipset.  Resizing
> the screen triggers the mentioned bug.
> 
> The workaround is to make vgacon avoid calling vgacon_doresize() if the
> display parameters did not change. It also has a nice side effect of faster
> console switches, but that will be barely noticeable.

This patch really deserves a comment in the code that such a broken hardware
exists.

Also, I don't see much reasons for introducing VGA_FONTWIDTH, it seems to only
complicate the code.

				Have a nice fortnight
-- 
Martin `MJ' Mares   <mj@ucw.cz>   http://atrey.karlin.mff.cuni.cz/~mj/
Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
For every complex problem, there's a solution that is simple, neat and wrong.
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