xrandr dual head issues

lambretta · 2009-12-29 11:58:57

Hello all. Have had Arch running fine for months using Openbox.

Hardware...

IBM Thinkpad T41p
ATI Video card FireGL mobility T2
Laptop (LVDS) 1400x1050
External monitor (VGA-0) 1360x768

Firstly, I was successful in getting two displays working with xrandr. LVDS and VGA-0 as separate displays, VGA-0 was to the right of the LVDS. I was really happy with the lack of effort it took to make this work.

When playing a video using mplayer or VLC the image displays fine on LVDS but once I drag it more than 50% onto the VGA the image disappears (although sound continues). You-tube played in the web browser plays fine on both displays.

Thinking it may be an xorg.conf issue I went to look at the xorg.conf and..... there is none, it wold appear its using built in defaults going by Xorg.0.log

So after creating and xorg.conf and messing with it I can no longer display the VGA-0 to the right of LVDS, it says maximum width is 1400 and I want 2760 which all makes sense and I see the fix for this is to add a Virtual screen line in the xorg.conf to be able to accommodate the two screen side by side.

My two question, if anyone could help, are:-
1.Is there any way to change the Virtual screen size without messing with xorg.conf?
2.What is the likely reason for not being able to display a video on the VGA-0 screen?

Thanks for reading,

Cyrusm · 2009-12-29 14:47:03

There is no way to change your virtual screen size that I know of outside of Xorg.conf.
but it's not exactly like you're "messing with it." you're adding ONE line. don't be a wuss
just copy to a backup just in case. add the virtual line to the Display subsection of the Screen section.

if you want to see how large of a virtual screen your graphics driver can handle, run "xrandr -q" and check the maximum.
make sure your virtual desktop fits within these dimensions.

http://www.thinkwiki.org/wiki/Xorg_RandR_1.2

also, if you ever have the time and the inclination, I suggest writing your own xorg.conf from scratch one of these days
it's a great learning experience and makes troubleshooting graphics issues later on much easier

EDIT: oh yeah, do you think you could post your xorg.conf so we could take a look at it? make sure everything is correct
and whatever?

Last edited by Cyrusm (2009-12-29 16:43:45)

R00KIE · 2009-12-29 14:57:58

If VGA-0 was to the right of LVDS then the virtual screen size was big enough to accommodate both screens.

As I'm posting I have a smaller monitor connected to my notebok (VGA-0 is at the right of LVDS and) videos play just fine, I'm using smplayer and I've tried to use all output modes, all the output modes that actually work display videos just fine in both displays.

Which driver did you say you are using? Things work just fine here with xf86-video-ati (rv610 or r610 or whatever ... it should be a mobility radeon hd2400).

lambretta · 2009-12-30 00:58:08

ROOKIE wrote:

If VGA-0 was to the right of LVDS then the virtual screen size was big enough to accommodate both screens.

Your dead right, it did work but now for some odd reason the virtual screen size is no longer large enough to accom' both screen.

ROOKIE wrote:

Which driver did you say you are using?

I installed xf86-video-ati and assume it is loading fine.

Cyrusm wrote:

oh yeah, do you think you could post your xorg.conf

I would love to but I do not have such a thing, I can post my Xorg.0.log if you would like to take a look. I believe I am trusting HAL to auto configure each time so xorg.conf doesn't exist. All seems like black magic to me but to date has worked well.

Will I need to create an xorg.conf file, populate it and get it working to be able to use both screens as well as to be able to play video on VGA-0?

I can duplicate LVDS onto VGA-0 but again video will not play on VGA-0.

Thank you both so far with you help. Would love to sort this out and if I need to get dirty with and xorg.conf file then so be it.

R00KIE · 2009-12-30 15:52:17

If you want to have the screens side by side you will have to create a xorg.conf and define a large enough virtual screen where both can fit.

As for why video doesn't display on VGA-0 ... I don't have a clue, I've tested with mplayer+smplayer (which is what I use reularly) and it worked fine with all output modes that worked for me (the ones that didn't work either made mplayer crash or didn't output video at all).

I am using a xorg.conf, maybe you can start with one that works for you and make VGA-0 the same as LVDS to start debugging, then move on to put the screens side by side.

signor_rossi · 2009-12-31 10:03:56

I have a similar setup as yours and can't do without the 'Virtual' line in xorg.conf. I also guess that our graphic card limitations are similar (what's the chip id of your's, mine is RV380), so you probably can't use all video output modes the radeon driver offers, normal xv and xv textured video. Which one are you using ('Settings/Preferences' undermenu in smplayer and vlc)? You can also use X11 video output as an alternative. Additionally, do you use KMS or did you disable it?
BTW, I can't get fullscreen output in VLC at all, no matter what output method I use, smplayer works with normal xv.

Last edited by signor_rossi (2009-12-31 10:10:31)

R00KIE · 2009-12-31 14:09:27

My card is an RV610, for me XV, XV Textured Video, X11, gl, gl (fast), gl (fast - ATI Cards), gl (yuv), gl2, gl2 (yuv) and SDL work well in smplayer+mplayer, also I can get vlc to go into fullscreen (default settings).

I'm not using kms because for me it doesn't work at the moment, all the packages I'm using now come from the stable repos.

All I can add is that the secondary screen I'm using is an old crt with a maximum resolution of 1024x768. Setting vga-0 the same as lvds works as well as putting the secondary screen to the right of lvds.

Arch Linux

#1 2009-12-29 11:58:57

xrandr dual head issues

#2 2009-12-29 14:47:03

Re: xrandr dual head issues

#3 2009-12-29 14:57:58

Re: xrandr dual head issues

#4 2009-12-30 00:58:08

Re: xrandr dual head issues

#5 2009-12-30 15:52:17

Re: xrandr dual head issues

#6 2009-12-31 10:03:56

Re: xrandr dual head issues

#7 2009-12-31 14:09:27

Re: xrandr dual head issues

Board footer