[mythtv-users] Weird HDMI problem

Igor Cicimov icicimov at gmail.com
Wed Apr 4 00:51:50 UTC 2012

> On Wed, Apr 4, 2012 at 6:34 AM, Calvin Harrigan <
> charriglists at bellsouth.net> wrote:

On 4/3/2012 3:38 PM, Nick Rout wrote:
> <snip>
>>> I've had similar problems related to this chicken, egg issue.  I even
>>> had a
>>> problem with getting the audio over the HDMI cable because of an errant
>>> edid. Both were fixed with the same solution.  Extract the edid from your
>>> tv, save it to a file.  Instruct xorg to use the file for the TV info,
>>> negating the need to ask the TV directly.  If the TV is off this will
>>> return
>>> nothing, which will result in a blank screen when you finally turn on the
>>> TV.  Detailed instructions can be found here:
>>> http://analogbit.com/fix_**nvidia_edid<http://analogbit.com/fix_nvidia_edid>
>> Only works on nvidia AFAIK
>>  Luckily for you, you won't have to edit the edid data, recalculate
>>> checksums
>>> and the like. I had to do this to strip away the audio information
>>> provided
>>> by the TV, which prevented me using the TV the way I wanted to.
>>>  Sorry, I forgot that critical piece of information.  You did mention
> ATI.
> Might still be possible:
> Which driver are you using?  fglrx or open source? The open source ones
> seem to work with the custom-edid opiton
> http://en.gentoo-wiki.com/**wiki/Radeon#Custom_EDID<http://en.gentoo-wiki.com/wiki/Radeon#Custom_EDID>
> http://manpages.ubuntu.com/**manpages/lucid/man4/radeon.4.**html<http://manpages.ubuntu.com/manpages/lucid/man4/radeon.4.html>
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First thanks to everyone for your response and suggestions.

Unfortunately I use fglrx driver which doesn't have the CustomEDID option.
The option is supported by the radeon opensource driver but not by fglrx.
Sorry I missed to mention the fact I have the latest 12.2 Catalist driver
installed (hoping ATI will solve the problem so I keep up to date) which
I'm not sure is better than the radeon one but I get really smooth playback
in Mplayer with gl/gl2 video output so I'm not really ready to switch over.

I can also confirm that including Modline in the xorg.conf doesn't work as
pointed by Jean-Yves.

I found it best to disable DPMS power saving in xorg.conf:
> Section "ServerFlags"
>        Option      "BlankTime" "0"  # default 10 mins
>        Option      "StandbyTime" "0"  # DPMS standby, default 10 mins
>        Option      "SuspendTime" "0"  # DPMS suspend, default 10 mins
>        Option      "OffTime" "0"  # DPMS off, default 10 mins
> EndSection

Lawrence, I find your suggestions very interesting I can see you had
battled this problem before :) I have the ServerFlags section already
included in my xorg.conf but without any success. I have to check if I have
the correct options set as given above though.

This is almost certainly the ATI radeon driver disabling any
> disconnected outputs.  I had the same problem with an analog TV
> connected to TVout.  I fixed it by adding this to xorg.conf:
> Section "Device"
>        # copy existing
>        ....
>        Option          "ForceTVOut" "on"
>        # The above is documented for the radeon driver
>        # For fglrx use:
>        Option          "NoTV" "no"
> EndSection

I'm certainly going to try this option!

sudo xrandr --output HDMI1 --auto

This is exactly what I was looking for, a way to probe the HDMI output
without removing/inserting the cable!

Thanks again guys, I'll try the things suggested tonight and report back.

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