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View Full Version : boot mythtv with tv off causes blank screen



jeremycobert
October 6th, 2009, 07:26 PM
hey guys, if i have my TV off and i remotely reboot mythbuntu (8.10) and later turn the tv on ,it will not respond to any remote control actions. it is on as i can vnc back into it and play shows, but the signal never get to the TV.

if i boot with the tv on, then there are no problems. i assume its a focus issue, im just not sure how to resolve it, other then logging out or rebooting.

any ideas ?

SiHa
October 6th, 2009, 08:18 PM
Firstly, I'm not sure how much dependance 8.10 has on xorg.conf. I know by 9.04 it's been sidelined with the server doing more of the auto-setup at boot.

I'll make a couple of assumptions that you've got an nvidia card with VGA and DVI out, and the TV is connected to the DVI. Also that 8.10 does use xorg.conf.

Please note It's a good idea before editing xorg.conf, to back it up.
sudo cp /etc/X11/xorg.conf xorg.conf.bakShould it all go **** up, and the pc won't boot to any GUI, you can restore the file. You just drop to a root prompt from the GRUB menu, and copy the backup file back on top of the damaged one.

The problem I think you have is that the X-server will attempt to validate the required display mode by polling the attached monitor for EDID information - essentially an EEPROM in the monitor/TV with a list of supported resolutions & display rates. If it can't find anything it generally will fall back to something like 640x480 on the VGA port.

I had the same problem with my frontend (8.04), but I've edited my xorg.conf to tell it to ignore whatever it thinks is connected and just squirt the display out of the DVI port.

Here's my /etc/X11/xorg.conf

# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings: version 1.0 (buildd@vernadsky) Tue Mar 4 20:24:34 UTC 2008


Section "ServerLayout"
Identifier "Default Layout"
Screen 0 "Screen0" 0 0
InputDevice "Generic Keyboard"
InputDevice "Configured Mouse"
EndSection

Section "Module"
Load "glx"
EndSection

Section "ServerFlags"
Option "Xinerama" "0"
EndSection

Section "InputDevice"
Identifier "Generic Keyboard"
Driver "kbd"
Option "CoreKeyboard"
Option "XkbRules" "xorg"
Option "XkbModel" "pc105"
Option "XkbLayout" "gb"
EndSection

Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
Option "CorePointer"
Option "Device" "/dev/input/mice"
Option "Protocol" "ImPS/2"
Option "ZAxisMapping" "4 5"
Option "Emulate3Buttons" "true"
EndSection

Section "Monitor"
Identifier "Generic Monitor"
Option "DPMS"
EndSection

Section "Monitor"
Identifier "Monitor0"
VendorName "Unknown"
ModelName "Panasonic-TV"
HorizSync 15.0 - 68.0
VertRefresh 23.0 - 61.0
modeline "1280x720@60" 74.25 1280 1390 1430 1650 720 725 730 750 +hsync +vsync
EndSection

Section "Device"
Identifier "Generic Video Card"
Driver "nvidia"
Option "DPI" "100x100"
Option "UseEvents" "1"
Option "AddARGBVisuals" "1"
Option "AddARGBGLXVisuals" "1"
Option "NoLogo" "1"
EndSection

Section "Device"
Identifier "Videocard0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce FX 5200"
EndSection


Section "Screen"
Identifier "Screen0"
Device "Videocard0"
Monitor "Monitor0"
DefaultDepth 24
Option "TwinView" "0"
Option "ConnectedMonitor" "DFP"
Option "ExactModeTimingsDVI" "TRUE"
SubSection "Display"
Depth 24
Modes "1280x720@60"
EndSubSection

EndSect

The important statement is the
Option "ConnectedMonitor" "DFP". This tells it to send the output to the DVI port by defaukt. If you're not using DVI, but S-Video, you could change it to
Option "ConnectedMonitor" "TV"


With any luck, this will get the signal sent out of the correct port.

If this works, you might want to look here (http://ubuntuforums.org/showthread.php?t=83973) if your resolution's screwed when booting with the TV off.

Shibblet
October 6th, 2009, 08:27 PM
hey guys, if i have my TV off and i remotely reboot mythbuntu (8.10) and later turn the tv on ,it will not respond to any remote control actions. it is on as i can vnc back into it and play shows, but the signal never get to the TV.

if i boot with the tv on, then there are no problems. i assume its a focus issue, im just not sure how to resolve it, other then logging out or rebooting.

any ideas ?

Sounds to me like an HDMI issue. If that is how you have it hooked up. HDMI talks back from TV to Device. This is an internal issue wit you TV, and the TV has to be turned on first to make the HDMI component aware of it's existance.

I see this problem with DVD players and Blu-Ray players on older (2 years) TV's all the time.

If it's DVI, it's the same issue. DVI is the first-born of HDMI, and it came with the power on problem.

My guess is with a Panasonc 720p Plasma, you are using HDMI as they don't have VGA connections on them.

jeremycobert
October 6th, 2009, 09:03 PM
hey guys thanks, it is hdmi (LG) which may be the issue, i may just wait until 9:10 is finalized and just live with it until then.
i just wanted to see if it was something simple i was missing.

thanks for your replies

superm1
October 7th, 2009, 05:20 AM
You can capture the EDID using nvidia-settings while the TV is on and save that somewhere. There is an xorg.conf option for using the pre-saved EDID exactly for this scenario.