G35 HDMI with Intel driver through a HDMI 4-1 switch

Petri Helin phelin at googlemail.com
Fri Aug 29 11:21:55 PDT 2008


I have a Asus P5E-V HDMI motherboard, based on G35 chipset. The board 
has VGA, DVI and HDMI connections. VGA works splendidly, DVI I haven't 
tested, but HDMI is causing a lot of trouble.

I tried with HDMI connection from the computer to a video projector thru 
  a HDMI-switch. This worked with my previous set with nvidia display 
card, I could even see that EDID came all the way to the nvidia card. 
Now, with Intel IGP, the projector is no more recognized. Executing 
xrandr it reports that I have a VGA and a TDMS-1 monitors.

Then I connected the HDMI straight to the projector. Now xrandr reports 
VGA and HDMI-1 monitors, but still EDID is not being read or at least 
there are no entries in Xorg.0.log that would imply it. Though it sets 
the resolution to 1280x720 at 60 which is the native resolution. For VGA 
monitor there are entries in the log for EDID being read. Still, now I 
got picture to the projector.

I have tested with both the driver which comes with Ubuntu 8.04 (version 
2.2.1) and version 2.4.1. No difference.


1. What is the difference between TMDS and HDMI?
2. Why doesn't it work when the switch is in between the computer and 
the projector?


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