1440x900 no clock available for mode?

Luc Verhaegen libv at skynet.be
Thu Aug 3 12:05:07 PDT 2006

On Thu, Aug 03, 2006 at 11:15:56AM -0600, drew at technteach.com wrote:
> Trying to set a custom ModeLine to get support for 1440x900 to support
> my brand new wide screen lcd panel
> full xorg.conf, and Xorg.0.log at the end of this message.  but first
> I'll explain, what I tried with snippets from these files.
> I began with a xorg.conf generated by the system config utility on my
> Fedora FC5 box.
> Played around with the FC5 gui config tools.
> Tried using gtf to generate some custom ModeLines

> but no matter what I try when X starts up it burps and ignores it with
> something like the following
> (II) VIA(0): Not using mode "1440x900" (no clock available for mode)

snippet from your log:
 (II) Module via: vendor="X.Org Foundation"
        compiled for, module version = 0.1.33
        Module class: X.Org Video Driver
        ABI class: X.Org Video Driver, version 0.8

This apparently predates both (unichrome and openchrome) VT3122 dotclock 
generators. There's free modesetting, but at that time it was limited to
a list of known stable dotclocks, for the most common modes only.

VT3122 pll is a rather akward beast. Dotclock generator wasn't easy to 
get stable while still allowing for sufficient granularity.

Some creativity with regard to the modeline might save you from 
compiling a driver yourself. Just look at the list of known dotclocks 
(it spent most of its life in via_mode.h), and pick one that's closest 
to the current dotclock.

If that still doesn't get you near enough, move the SyncStart and 
SyncEnd values equal amounts left, and reduce the Totals.

On the other hand, my driver uses some incarnation of my bug #5386 code, 
which gives you an unruly modelist which should include your panels 
preferred timing.

I'm not sure where Option "IgnoreEDID" came from. Iirc, VIAs idea of 
what Option "NoDDC" should've been was "NoDDCValue" and that got culled 
more than two years ago. grep tells me that IgnoreEDID is radeon 

Luc Verhaegen.

More information about the xorg mailing list