1280 x 800 video

Achim Bohnet ach at mpe.mpg.de
Tue Aug 9 13:58:31 UTC 2005


[Argl.  Sent too early wrong button :(]

On Tuesday 09 August 2005 15:52, Achim Bohnet wrote:
> On Tuesday 09 August 2005 02:28, Ed Cogburn wrote:
> > Derek Broughton wrote:
> > 
> > > After much hassle, and the suggestion from someone here to use gtf, I got
> > > my Dell Inspiron to display 1280 x 800 (the native resolution when I
> > > started it up in Windows).
> 
> What is gtf?
> 
> I've a similar problems with Dell Latitude X1: only 1024x768 instead
> 1280x800 (no virtual display overlayed).  I'll try to get the laptop
> again.  But xorg as as created during installation.
> 
> > > However, kdm comes up in a 1280x800 _virtual_ screen, on 1024x768 physical
> > > pixels.  Then when I log in, I have to manually switch it to 1024x768 to
> > > make the physical and virtual screens match, then set it back to 1280x800
> > > to make it _really_ show the widescreen format.
> > > 
> > > What do I need to do to make the monitor automatically show 1280x800?
> > 
> > 
> > Do you have a virtual resolution setting in your xorg.conf?
> 
> I've a similar problem on a Iiyama AU4831D 19'' TFT:
> 1600x1200 virt screen on 1024x768. No virtual setting in xorg.conf.
> Problem here is:
> 
> ...
> (II) RADEON(0): First detailed timing is preferred mode
> ...
> (II) RADEON(0): Panel infos found from DDC detailed: 1024x768
> (II) RADEON(0): Panel infos found from DDC VESA/EDID: 1280x1024
> (II) RADEON(0): Valid Mode from Detailed timing table: 1024x768
> (II) RADEON(0): Valid Mode from Detailed timing table: 1600x1200
> (II) RADEON(0): Valid Mode from standard timing table: 1280x1024
> ...
> (WW) RADEON(0): Mode 1600x1200 is out of range.
> (WW) RADEON(0): Valid modes must be between 320x200-1280x1024
> (WW) RADEON(0): Mode 1600x1200ach is out of range.
> (WW) RADEON(0): Valid modes must be between 320x200-1280x1024
> ...
> The 'first detailed ...' is 1024 not 1600.  Unfortunately I've found
> no way yet to override the 'prefered mode' :(
> 
> When I connect via VGA instead of DVI 1600x1200 works fine.
> Booting with a Dell 2005FP or Siemens P20-1 (both 20'' 1600x1200)
> DVI works with 1600x1200 with the same xorg.conf.  Unpluging
> does Monitors and plugin in the Iiyama and 1600x1200 works.
> 
> So it's DDC or EDID of the Iiyama

... 19'' TFT that confuses the xorgs radeon driver (same with
i810 driver too).

Achim
> 
> > 
> > A scenario where I see this could happen is you have set a virtual screen
> > size of 1280x800 but X is unable to actually set the 1280x800 resolution
> > later on, so it drops back to the first one it can, in this case 1024x768,
> > but the virtual screen size setting is still in effect.  Have you looked at
> > the Xorg log to see what error messages its showing?  Its probably
> > rejecting the 1280x800 resolution for some reason, and instead taking the
> > first one that looks good to it.
> > 
> > A virtual setting in the screen section is actually unnecessary, just
> > arrange your modes on the 'Modes' line so that the one you want is the
> > first one, but keep them in wrap-around, left-to-right size order so that
> > the Alt- +/- keys are still useful.
> > 
> > 
> > > Also, it seems I always had Ctrl-Alt-+ and Ctrl-Alt-- to change the
> > > desktop size in Debian (though, since I rarely used it, perhaps it wasn't
> > > always there).  How come this doesn't work in Kubuntu?
> > 
> > 
> > Unfortunately, I customized my config early on for high-res gtf modes, so if
> > ubuntu/kubuntu is doing something differently, I don't know what it would
> > be.  The Alt- +/- keys work fine for me, if they don't it usually means
> > only one resolution is being declared on the 'Modes' line.  If none of
> > those modes work, Xorg will simply fall back to one that it autodetected or
> > a VGA/VESA builtin mode, which could be the 1024x768 your seeing.
> > 
> > Without seeing your xorg.conf, its really hard to say anything for sure.
> > 
> > If it helps, below is the parts of my xorg.conf that handle the modes.  I've
> > truncated some stuff to prevent line breaking, and left out unrelated
> > stuff.  My modes section has more than 3 modes (starts at 320x240), but I'm
> > just using 3 here to show the size order thing.  I never specify a default
> > nor virtual resolution, Xorg sets those based on the first (valid) mode it
> > sees on the 'Modes' line in the 'Screen' section.
> > 
> > 
> > Section "Modes"
> >  Identifier "Y120 Custom Modelines"
> >  ...
> >  #1400x1080 at 120 Hz (GTF) hsync: 138.84 kHz; pclk: 269.90 MHz
> >  Modeline "My_1400x1080" ...
> >  #1600x1200 at 110 Hz (GTF) hsync: 140.58 kHz; pclk: 312.65 MHz
> >  Modeline "My_1600x1200" ...
> >  #1760x1320 at 100 Hz (GTF) hsync: 139.80 kHz; pclk: 339.99 MHz
> >  Modeline "My_1760x1320" ...
> > EndSection
> > 
> > Section "Monitor"
> >  ...
> >  UseModes "Y120 Custom Modelines"
> > EndSection
> > 
> > Section "Screen"
> >  ...
> >  DefaultDepth 24
> >  ...
> >  SubSection "Display"
> >   Depth 24
> >   Modes "My_1760x1320" "My_1400x1080" "My_1600x1200"
> >  EndSubSection
> > EndSection

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