Re: X: Changing resolution

["Donald R. Spoon" <dspoon@satx.rr.com>]

Steve Dondley wrote:

> Problem:
> Pressing CTRL-ALT-+/- (numeric) doesn't change my screen resolution setting.  
> X (with sawmill) always starts out in 1024 x 768 with 16 bpp (65,000 colors) 
> and I can't figure out how to change it. 
>  
> Background:
> For practice, I just installed X from scratch.  I configured the XF86Config 
> file with xf86config.  I've  > got 1 MB of video ram on an S3 chipset.  I set 
> three resolution settings with the program:
> 1024 x 768 at 8 bpp,
> 1024 x 768 at 16 bpp,
> and 800 x 600 at 24 bpp.
>  
> Question:
> How do I change monitor resolution/color depth in X?  To put it another way, 
> how do I get CTRL-ALT-+/- to work?
>  
> Thanks.  This is a great list.

First of all, I "think" the "CTRL-ALT-+/-" key sequence will work to
change display RESOLUTIONS but not COLOR DEPTH.  That eleminates any
action on the first two setting, since the only difference is color
depth (8bpp vs 16bpp).

Second, I question that you are indeed starting at a color depth of
bpp=16 at 1024 x 768 resolution.  I may be wrong here but, I calculate
that color depth/resolution would take a bit over 1.5 + megs of video
memory.  I would bet all you are getting is 1024 x 768 at 8 bpp.  This
observation also applies to the 800 x 600 at 24 bpp.  This color depth
would require about 1.4 megs of memory.  With only 1 meg of video memory
on your card, this resolution is NOT available.  You should be able to
get 800 x 600 at a color depth of 16 bpp, though.  Your card should also
be able to support 640 x 480 at 24 bpp too.

Here are the max resolutions/color depth I would expect from your video
card:

1024 x 768 at 8 bpp,
 800 x 600 at 16 bpp,
 640 x 480 at 24 bpp.

As a test, I would try changing your definations to suit the above, i.e.
drop the color depth back to 16 bpp on your 800 x 600 definition and see
if the CTRL-ALT-+/- key sequences works to switch it in.

Cheers,
-Don Spoon-