Re: Toshiba 1555CDS & X

[David Reviejo <dreviejo@arrakis.es>]

* Robert A. French <rfrench99@bigfoot.com> [000527 13:17]:
> I have a Toshiba 1555CDS laptop. Briefly: 380MHz K6-2, 32MB, S3-Virge
> MX (2MB). I have X up and running in 800x600 16bpp. However, any
> moderate CPU activity causes severe ghosting/streaking/whatever you
> want to call it. Originally, scrolling and such caused this, I
> alleviated this somewhat thru the "noaccel" option, but once I got
> some programs running, everything is bad again. I've fooled around
> with the color depth, the LCD clock, the PCI options, no luck. Any
> thoughts? I'm about ready to make my laptop console-only here.
> 

Hi Robert,

I have a Satellite 2540CDS, very similar at yours, and with the very
same problem.

Some months ago, and after some search, I found a similar problem in
"RedHat Linux on a Toshiba 220" (you can find this page in Linux on
Laptops), with this solution:

%   Once I got 16 and 24 bpp modes working, I was getting some nasty
%   visual jittering whenever I moved a window. Don't panic. All you
%   have to do is switch the display output (using Fn-F5). It doesn't
%   seem to matter whether you're using Display only or Display plus
%   Monitor (didn't have a monitor to check Monitor Only) - you just
%   need to cycle through the options once and the jittering goes away.

With the S3 Virge MX you need a second step; this is from the SVGA
documentation (README.S3V):

%   Whenever you switch output sources with Fn-F5 or similar, the
%   Xserver won't get informed and pixel clock and other settings are
%   wrong.  Because of this you have to switch modes _after_ switch
%   output sources!  Then the server will check which outputs are active
%   and select the correct clocks etc.  So the recommended key sequence
%   to switch output is
%
%       Fn-F5  Ctrl-Alt-Plus  Ctrl-Alt-Minus
%
%   and everything should be ok..
%
%   on the Toshiba keypad you can first hold down Ctrl-Alt, then press
%   `Fn' additionally before pressing Plus/Minus too to avoid to
%   explicitly enable/disable the numeric keypad for mode switching.

And for this to work, you need to define at less two modes for the
display depth you are using (if you have only 800x600 you can't switch
modes).

So, in short:
- define two modes for the display depth in XF86Config (the two modes
  can be the same 800x600).
- when you start X, switch output sources with Fn-F5 and then
- resyncronize the screen switching modes; you can do it with xvidtune;
  You'll need to do this also when you resume from an "apm -s" (NOT with
  Xfree 3.3.6).
- when you exit X, switch output sources with Fn-F5 (scrolling makes
  random horizontal lines if you don't do it); again, this step is NOT
  needed with 3.3.6 version.

Yes, it's an ugly workaround, but it work.

Cheers
-- 
David