[Wolves] where do i start??

James Turner james at turnersoft.co.uk
Sun Jul 23 10:24:35 BST 2006


On Friday 21 July 2006 12:46, David Morley wrote:

> On Friday 21 July 2006 12:33, James Daley wrote:
>
> > I changed it from vga to a low resolution and colours and the install
> > went fine, but when i start the machine without the cd the same happens.
> > Can i edit anything to put ut back to a low res??

It's supposed to figure out the correct monitor capabilities and resolution 
automatically, but as you can see, it doesn't always work properly, 
particularly with older hardware.

> Boot into safemode by pressing esc on the grub screen and selecting it
> then do sudo nano /etc/X11/xorg.conf and change the line in `Section
> "device" ` from what ever the driver is listed at to `vesa`

The above will cause a generic VESA framebuffer driver to be used, which 
should get around any problems that are caused specifically by the S3 driver. 
However, the problem could equally likely relate to the screen mode and 
monitor capabilities specified in the "Monitor" and "Screen" sections of 
xorg.conf.

The "Monitor" section defines the capabilities of the monitor in terms of 
minimum and maximum scan rates. Here's what it might look like for a generic 
640x480, 60Hz display (like an old fixed-frequency VGA CRT):

Section "Monitor"
        Identifier   "Monitor0"
        VendorName   "Monitor Vendor"
        ModelName    "Generic CRT Display 640x480"
        HorizSync    31.5
        VertRefresh  60
EndSection

The correct values of HorizSync and VertRefresh for the monitor are usually in 
the manual or can be found by Googling on the model name. Use a hyphen to 
specify ranges of values, e.g.:

        VertRefresh  50.0 - 85.0

Beware that the useful lifetime of the monitor can be greatly reduced by 
entering values outside of it's rated capabilities. Many monitors will 
automatically switch the display into a power saving mode or show a "Signal 
out of range" message instead to protect themselves if the values are way 
off.

The "Screen" section is used to specify the actual colour depth and resolution 
to be used. Example:

Section "Screen"
        Identifier "Screen0"
        Device     "Videocard0"
        Monitor    "Monitor0"
        DefaultDepth     16
        SubSection "Display"
                Viewport   0 0
                Depth     16
                Modes    "1024x768" "800x600" "640x480"
        EndSubSection
EndSection

Appropriate refresh rates for each mode will be chosen automatically based on 
the capabilities listed in the "Monitor" section. With multiple modes listed 
(as above), you can use CTRL+ALT+KeypadPlus and CTRL+ALT+KeypadMinus to cycle 
through them whilst X is running. (This is sometimes used as a "zoom" 
facility).

To force 640x480, just take out all the other modes. The "Depth" value (and 
"DefaultDepth") specifies the colour depth 16bit - 65536 colours, 8bit - 256 
colours, 4bit - 16 colours. It's been a long time since I've had to start X 
in a 16 colour mode to get it working... not nice. Any modes that exceed the 
graphics card's video RAM will be automatically removed from the list. If 
every mode is removed from the list in this manner then X will fail to start 
up, with an error message that no modes are available.

As Mr. Maaaaaarley states above, the easiest way to test this is to boot into 
single user mode (presumably this is the same thing as what is called "safe 
mode" in Ubuntu). Once you've edited the xorg.conf file, type "xinit" or "X" 
to start up a minimal graphical display. (Depending on the path setting you 
may need to type the full pathnames, probably "/usr/X11R6/bin/xinit" or 
"/usr/X11R6/bin/X"). To quit out of the graphical display when satisfied that 
it's working, or to do more editing of xorg.conf, press CTRL+ALT+Backspace. 
Once everything is to your liking, you can run the rest of the boot sequence 
to bring up the graphical login prompt by typing "telinit 5" (or 
"/sbin/telinit 5"), or just doing a reboot as per normal (CTRL+ALT+DEL).

Regards,

James



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