915resolution for Live CD? (Re: Dapper install from live CD)

Karl Hegbloom hegbloom at pdx.edu
Tue Jun 6 05:10:16 BST 2006

On Mon, 2006-06-05 at 11:56 -0400, Sarunas Burdulis wrote:
> How do you start Dapper install from the live CD? I'm doing this on a
> laptop where X fails to start (it needs 915resolution). Ubuntu live has
> booted and I'm looking at a regular shell prompt. `setup`, `install`,
> `d-i` don't help.

I've got a laptop with a similar problem... the screen has 1400x1050
native resolution, but the VBIOS does not have a mode for it.  Xorg
prints the true resolution in the log, and so is probably able to detect
that via DDC, but it does not know how to do the thing that
915resolution does.  It starts the Live CD at 1280x1024, which is usable
albeit a bit fuzzy.

I wonder if there's a way to auto-detect the LCD native resolution, and
automatically write a configuration file for 915resolution?  'ddcprobe'
does not show the right information...

 sudo discover --enable=pci --xdriver video

... prints 'i810' twice, once for each pipe.  If I then run:

 sudo Xorg :1 -probeonly

... and look in /var/log/Xorg.1.log, I find:

 (II) I810(0): Display Info: LFP (local flat panel): attached: TRUE, present: TRUE, size: (1400,1050)

I imagine that doing this is probably safe given that (a) laptop=true,
and (b) --xdriver is one of the cards supported by 915resolution.  I'm
also reasonably sure that mode 3c (for 915resolution) is going to be
free for use in all if not most configurations.

I seem to recall seeing something out there about having Xorg perform
that mode fixup itself; I think somebody may even have written a patch
for it at some point...  Search for "a future" in:


Karl Hegbloom <hegbloom at pdx.edu>

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