[mythtv-users] Display only detected sometimes, "low-graphics mode" rest of time

James Crow james at ultratans.com
Tue Jun 17 18:27:06 UTC 2008

On Tue, 2008-06-17 at 10:43 -0700, Allen Edwards wrote:
> I just upgraded my myth box from a 2.4GHz P4 to a AMD 5400+.  This is
> my first AMD machine and it isn't going that well.  Besides the air2pc
> card problem in another post, this machine boots up fine sometimes and
> boots up with this message some times:  "Ubuntu is running in
> low-graphics mode".  This is with nvidia 5+ driver.  It seems the
> problem is that the ASUS 6200 PCI-E card is recognizing the Samsung
> 193p+ only some of the times.  I never had a problem with this monitor
> in mythbuntu with the P4 system and the EVGA 6200 AGP card.
> Does anyone know if this means I have defective hardware?  I think I
> have like 7 days to send stuff back if needed.
> Anyone else have this problem?
> I searched for a solution and of course, there are lots of advice how
> to get rid of this error when it is permanent (install the drivers)
> but nothing for a sometimes problem.
> Allen
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I have a couple of Panasonic 50" plasma sets connected to Ubuntu 7.10 by
50' DVI->HDMI cables and the computer is not able to read any EDID info
from them. What I did was hookup a short (6' RadioShack brand) DVI->HDMI
cable. With that cable I could sometimes get EDID info from the TVs.
With the short cable connected I started X with 'start -- -logverbose 6'
and then looked through /var/log/Xorg.0.log to find the raw EDID bytes
from the TV. Once I had the EDID info I saved it into a file and told
the Nvidia driver to use that. I also had to set a few overrides because
many older TV sets give out conflicting EDID info. Once that was done I
got a consistent picture on the sets. Here is a bit of
my /etc/X11/xorg.conf file with some of the relevant info:

Section "Device"
        Identifier      "Failsafe Device"
        Boardname       "vesa"
        Busid           "PCI:0:5:0"
        Driver          "nvidia"
        Screen  0
        Option          "AddARGBVisuals"        "True"
        Option          "AddARGBGLXVisuals"     "True"
        Option          "NoLogo"        "True"
        #Option         "ModeValidation"
        # The next line works and allows both 1080i and 720p, but 1080i
is shaky
        #Option         "ModeValidation"
        Option          "ModeValidation" "DFP-0:
        Option          "connectedMonitor"      "DFP-0"
        Option          "CustomEDID"

There is a lot of extra crap in there from my testing. The best thing I
found when fighting with a set was to always start X from the command
line with logverbose 6. If you have a certain mode that is failing the
Xorg.0.log file will tell you why the driver rejected it. My TV at home
was quite a problem until I upgraded to Mythbuntu 8.04. Prior to that I
fought with it and an onboard 6150. Now that I use an 8400 PCI-e card
the driver can autodetect everything just fine. I don't know if the
newer card or the driver were the fix, but things are better now for me.


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