Unsynced TMDS with xf86-video-intel on 945GM

René Rebe rene at exactcode.de
Wed May 16 13:37:08 PDT 2007

On Wednesday 16 May 2007 21:36:22 Keith Packard wrote:
> On Mon, 2007-05-14 at 09:18 +0200, René Rebe wrote:
> > However often (like about 80% of the X starts) I get flickering and rolling thru
> > pixel trash on the external display. It "looks" like there is some sync (or so)
> > missing or imprecise, as it's the actual desktop pixel content flushing and
> > shuffling by.
> > This can be fixed by re-enabling the LVDS and disabling it again:
> Sounds like the mode programming has some stability issues; the
> registers in the chip must be programmed in the right sequence and with
> the right delays between various steps in the process. Failing to wait
> long enough for a PLL to lock can result in 'bad' behaviour like this.
> About the only way to debug this is to add delays at various points in
> the mode setting operation, most likely the CRTC timing programming,
> although it's possible that the SDVO programming is broken instead.
> One thing to always try is the latest development version of the X
> server and intel driver; there are a few minor fixes which may be
> related. Plus, patches you come up with won't need to be ported forward.

Do you have an explanation why the distortion on the TMDS-1
is mostly disappearing when I rotate the 3D desktop cube?

I would rather expect the "mis-programmed" TMDS output
to have a static noise than changing with 3D engine load, ... ?


  René Rebe - ExactCODE GmbH - Europe, Germany, Berlin
  http://exactcode.de | http://t2-project.org | http://rene.rebe.name

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