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

Petri Helin phelin at googlemail.com
Wed Sep 3 06:35:59 PDT 2008


Petri Helin wrote:
> On Fri, Aug 29, 2008 at 9:21 PM, Petri Helin <phelin at googlemail.com> wrote:
>> Hi,
>>
>> 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.
>>
>> Questions:
>>
>> 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?
>>
>> -Petri
>>
> 
> Well, I should have tested a bit more...  I switched back to using the
> switch betwenn the computer and the projector, and now it works. I
> cannot fathom why it didn't work earlier. Must have been just a loose
> cable or something.  The connection is still named TMDS-1 instead of
> HDMI-1, though.
> 
> -Petri
> 

Hi again,

please put all of the above to me just familiarizing myself with intel
driver... I have now gotten some understanding, but one thing I cannot
figure out:

I have a TV connected through VGA with resolution 1360x768 at 60 and a
projector connected through HDMI with resolution 1280x720 at 50 or
1280x720 at 60. I'd like to get either the picture on both outputs at those
resolutions, or that's not possible, then one at time. Or that's what I
am aiming at.

Once X has started, I get picture on both displays and xrandr outputs
the following:

Screen 0: minimum 320 x 200, current 1360 x 768, maximum 1360 x 1360
VGA connected 1360x768+0+0 (normal left inverted right x axis y axis)
885mm x 498mm
    1360x768       60.0*+
    1024x768       75.1     70.1     60.0
    800x600        72.2     75.0     60.3
    640x480        75.0     72.8     60.0
    720x400        70.1
HDMI-1 connected 1280x720+0+0 (normal left inverted right x axis y axis)
1600mm x 900mm
    1280x720       60.0*+   50.0
    640x480        60.0

Now, that looks very nice. But, the projector itself says that it is
getting signal with "DVI" resolution, when it should say it is getting 
720p. My intention is to use xine to output video on both displays, and 
if I now open it up with fullscreen setting it is perfect in the TV but 
on the projector it looks like it is too getting 1360x768, since right 
and bottom sides of the image are clipped. Xine-lib frontend I am using 
also seems to confirm it:

Display size : 876 x 494 mm
               1360 x 768 pixels
               39dpi / 39dpi
Display ratio: 1554.655870/1552.511416 = 1.000000


If I turn the VGA monitor off, with "xrandr --output VGA --off" and 
query the state with xrandr, it shows this:

Screen 0: minimum 320 x 200, current 1280 x 720, maximum 1360 x 1360
VGA connected (normal left inverted right x axis y axis)
    1360x768       60.0 +
    1024x768       75.1     70.1     60.0
    800x600        72.2     75.0     60.3
    640x480        75.0     72.8     60.0
    720x400        70.1
HDMI-1 connected 1280x720+0+0 (normal left inverted right x axis y axis) 
1600mm x 900mm
    1280x720       60.0*+   50.0
    640x480        60.0

Now at least I would interpret this so, that the whole image should be 
shown in the projector. But no, it is still clipped and still showing 
"DVI" instead of "720p" on the projectors info screen. But, the xine-lib 
frontend claims it is using 1280x720:

  Display size : 823 x 463 mm
                 1280 x 720 pixels
                 39dpi / 39dpi
  Display ratio: 1555.075594/1555.285541 = 1.000000


Is there any way to get true fullscreen output in the projector? I don't 
really care if it shown in the TV at the same time or not. And is the 
signal I am feeding to the projector realy 1280x720, as xranr claims it 
to be, or something else?

-Petri






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