[ltp] DVI output from X20

[Alex Deucher]

On 9/1/05, Rolf Leggewie <no2spam@nospam.arcornews.de> wrote:
> Hi,
>=20
> I got a new TFT display and since the picture shows some shadows when I
> connect the X20 through the dock, I thought I'd use the DVI connector
> rather than the analog signal.  But then, there is absolutely no picture
> displayed :-( not at boot-up and not later.  I am at a loss.  Anybody
> got this setup working?  Any other comments?
>=20

I'm not 100% sure how the DVI port is wired up in the docking
stations, so I don't know whether or not the station contains an tmds
transmitter or not.  Does it work in windows?  It may be that the DVI
only works with certain thinkpads.  I suspect the olders docks (for
X2x, T2x, A2x, etc. thinkpads) probably contain a tmds transmitter
that's wired up to the analog or DVO output of the graphics chip.  If
that is the case, you may have to mess with some GPIO or lines on the
GPU to program the tmds chip if the bios doesn't set it up for you.=20
Radeon and Rage128 chips have a build in TMDS transmitter, but the
stations don't seem to be wired up to use that.  This makes sense
because the mach64 and savage chips don't have a built in tmds cell,
so if the port was designed to be used by any thinkpad, you'd need
some chip agnostic method.

Alex

> Best regards
>=20
> Rolf
>