Bug#348873: regression: r128 on laptop ignores supplied modeline for external display, picking LCD panel pixel dimensions

Tim Connors tconnors at astro.swin.edu.au
Sun Jul 15 09:18:21 PDT 2007

On Sat, 23 Jun 2007, Tim Connors wrote:

> On Sat, 23 Jun 2007, Brice Goglin wrote:
> > Tim Connors wrote:
> > > and then Xorg.0.log goes on to claim it knows nothing about the IBM
> > > modelines:
> > > (II) R128(0): Not using mode "IBM_mode_1" (no mode of this name)
> > > (II) R128(0): Not using mode "IBM_mode_2" (no mode of this name)
> > > (II) R128(0): Not using mode "IBM_mode_3" (no mode of this name)
> > >
> > > Then I end up with cruddy 1024x768:
> > > (**) R128(0): *Mode "1024x768 at 75": 65.0 MHz (scaled from 83.9 MHz), 60.1 kHz, 74.4 Hz
> > > (which I find odd, because if it truly was using the flat panel's
> > > settings, should it not have picked up the 60Hz rate the flat panel
> > > requires?  It works on both displays when I cycle through the
> > > laptop's external/interal settings)
> > >
> >
> > Could you try with xserver-xorg-video-ati 1:6.6.192-1 currently in
> > experimental in case it helps?
> Same result with 1:6.6.192-1.
> > Or you feel more adventurous, you could try the randr-1.2 branch of the
> > upstream git repository since it should be better at discovering
> > modes/resolutions/... automatically without the need for anything in
> > xorg.conf. I have some packages of this somewhere if you want to try it.
> The latter certainly will be a problem -- I have good reason for wanting
> to supply my own modelines -- I have a fixed frequency external monitor.
> I don't need better discovery -- this all used to work, and I've already
> worked out which modelines will work on my monitor, and X will not do a
> better job than me at detecting necessary modelines from a monitor that
> doesn't do DDC.  This used to work prior to 6.9 -- I haven't changed
> anything to do with my carefully crafted modelines, so those should
> continue to be working.

A mandrake user has discovered a workaround, and I have just submitted
more info upstream to https://bugs.freedesktop.org/show_bug.cgi?id=5832

Bad assumptions seem to be made about the presense of flat panel registers
implying that a flat panel is being used.  I have proposed a more robust
workaround rather than the complete disabling of the
valid-modelines-for-a-flat-panel check, but wouldn't know how to actually
put this into action.

Hopefully someone knows enough about the driver to be able to check this.

"I give up," said Pierre de Fermat's friend. "How DO you keep a
mathematician busy for 350 years?"

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