Ext. VGA problem with Toshiba Portege R100 (TRIDENT, cyberbladeXP4)

[Mathieu Lacage]

This works without any problem on FC4's default server. It uses the vesa
driver.

Mathieu

On Thu, 2005-11-24 at 14:51 +0000, Markus Kuhn wrote:
> My Toshiba Portege R100 laptop uses a Trident XP4m32 graphics
> controller and an Intel 852GM chipset.
> 
> The X.Org 6.8.2 server (driver: TRIDENT, cyberbladeXP4) that comes with
> SuSE Linux 9.3 runs nicely with the built-in display.
> 
> However, as soon as I activate the VGA output (for use with a video
> projector) by pressing Fn+F5, the following strange effect happens:
> 
> The left half of the displayed image remains intact, but the right half
> gets replaced by two repetitions of half the left half of the image. In
> other words, if the image area is split horizontally into four
> rectangles, the second quarter gets repeated where the 3rd and 4th
> should appear, as in:
> 
> Expected image:
> 
>   +---+---+---+---+
>   |   |   |   |   |
>   | 1 | 2 | 3 | 4 |
>   |   |   |   |   |
>   |   |   |   |   |
>   +---+---+---+---+
> 
> Actually visible image (on both the LCD and the VGA output):
> 
>   +---+---+---+---+
>   |   |   |   |   |
>   | 1 | 2 | 2 | 2 |
>   |   |   |   |   |
>   |   |   |   |   |
>   +---+---+---+---+
> 
> This effect cannot be reversed by further uses of the Fn+F5 hot key to
> deactivate the external VGA. (I also cannot get out of it via xrandr.)
> 
> I suspect that the Fn+F5 hot key activates a BIOS system-management
> interrupt routine that reprograms the graphics controller completely,
> and that this reprogramming is incompatioble with the way the X.Org
> server drives this chip.
> 
> Detailed X server startup log:
> 
>   http://www.cl.cam.ac.uk/~mgk25/Xorg.log-Toshiba-R100.txt
> 
> Any ideas or suggestions?
> 
> Markus
> 
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