[SOLVED] Resolution problems when using VGA splitter between Desktop and TV

Eredeath · 04-14-2011, 11:20 AM

So I bought a VGA splitter and a long VGA cord so I could send the output to my new HD TV. It worked fine, I had my screen duplicated perfectly onto my tv. That is until I restarted the computer. Now everything is screwed up.

When I unplugged the TV and restarted it went back to detecting my monitor and it worked like before.

When I have both the TV and monitor plugged in, I can't get better than 800x600 resolution. I tried playing around with xrandr and followed a blog substituting my own resolution numbers in to create a 1680x1050 mode display... well one of the numbers (or more) must have been wrong because everything is just a little blurry and looking at the screen was starting to hurt my eyes.

So I unplugged the TV and restarted... and here I am looking for some help. If I plug in the tv right now, all is well. Then if i restart and leave the tv plugged in, my resolution goes to hell.
How do I stop it from auto detecting and changing my screen resolution?
I don't have a xorg.conf file, from what I've read Ubuntu 10.04 and up no longer uses one, so lets not go there if we don't have to.

MTK358 · 04-14-2011, 01:00 PM

What is the resolution of your TV?

Eredeath · 04-14-2011, 04:29 PM

Quote:

Originally Posted by MTK358

What is the resolution of your TV?

I'm actually not sure... its 1080p. I don't think that matters. When I had the tv running off the split signal the tv auto adjusted and it looked just fine. I'm not using it as a monitor per se, I'm using it to watch shows off of services like hulu.

MTK358 · 04-14-2011, 07:09 PM

1080p means 1920x1080.

http://upload.wikimedia.org/wikipedi..._scan_hdtv.svg

I thought that maybe your TV's resolution was much smaller than the monitor, and that that might cause issues.

Eredeath · 04-15-2011, 06:11 PM

I figured out a workaround that will do for now, but I will not mark the thread as solved until a more permanent solution is found. Here is what I did:

I booted the computer with the TV disconnected, used the command

Code:

xrandr --verbose

to get my current screen's settings.
Using those settings I created a script:

Code:

xrandr --newmode "MonitorAndTV" 146.2 1680 1784 1960 2240 1050 1053 1059 1089 -HSync -VSync
xrandr --addmode VGA1 "MonitorAndTV"
xrandr --output VGA1 --mode "MonitorAndTV"

and put it into my startup programs.

This of course is not ideal, my login screen is still in 800x600 resolution, if i create another user i would also have to duplicate the script and put it into their start ups... I would just like to unplug the TV, have it auto figure out the resolution then make that the default, and don't let it auto adjust again.

Eredeath · 04-15-2011, 06:55 PM

I found out how to make the script persistent. I followed these instructions from Ubuntu Wiki

Quote:

Setting xrandr commands in kdm/gdm startup scripts

Both KDM and GDM have startup scripts that are executed when X is initiated. For GDM, these are in /etc/gdm/ , while for KDM this is done at /etc/kde4/kdm/Xsetup. In either case, you can paste in an xrandr command line string into one of these scripts. For GDM, try putting them right before initctl -q emit login-session-start DISPLAY_MANAGER=gdm in /etc/gdm/Init/Default

Everything looks nice now. Hope this helps others.

MTK358 · 04-15-2011, 07:25 PM

Not sure if this will work for GNOME/KDE users, but here's the solution if you use startx:

Just enter the commands you want to run as X is started into ~/.xinitrc. It's basically a bash script that's run right after X is started.