[SOLVED] 3rd Monitor (ATI HELP)

[CeTis]

I have 2 ATI 5870s with crossfire disabled, ati drivers are installed and running properly.

I'm on my lunch break here at work just wondering how to get this third monitor to detect and work if possible.

[Cygn]

plug it ?

[CeTis]

Originally Posted by Cygn

plug it ?

ohh gee if only i hadz thoughtz of dat soonar...

nope, still not working.

---------- Post added at 11:12 PM ---------- Previous post was at 05:26 PM ----------

bump, someone has to know/have setup a 3rd monitor on ATI before....

---------- Post added 10th May 2012 at 12:20 AM ---------- Previous post was 9th May 2012 at 11:12 PM ----------

lspci is showing both cards and bus id:

02:00.0 VGA compatible controller: ATI Technologies Inc Radeon HD 5870 (Cypress)
07:00.0 VGA compatible controller: ATI Technologies Inc Radeon HD 5870 (Cypress)

this is what device in xorg looks like:

Section "Device"
Identifier "aticonfig-Device[0]-0"
Driver "fglrx"
BusID "PCI:7:0:0"
EndSection

Section "Device"
Identifier "aticonfig-Device[0]-1"
Driver "fglrx"
BusID "PCI:7:0:0"
Screen 1
EndSection

the problem is in CCC my dual monitors are working but the last slot says ["Unknown Display] Unknown Adapter".

[george_toolan]

ATI cards should support three monitors if you connect the third monitor with a display port cable.

[Cygn]

does the 3rd port shows in XRandr?
I remember succeding to activate a mis-detected display with "xrandr --output XXX --addmode 1280x1024" some time ago, with a radeon card. not sure if it was catalyst or OSS though.

[CeTis]

Originally Posted by george_toolan

ATI cards should support three monitors if you connect the third monitor with a display port cable.

Originally Posted by Cygn

does the 3rd port shows in XRandr?
I remember succeding to activate a mis-detected display with "xrandr --output XXX --addmode 1280x1024" some time ago, with a radeon card. not sure if it was catalyst or OSS though.

This issue has been resolved. First to answer both questions, 1 display port adapter is for third monitor with eyefinity but I don't plan on using that as I will probably get a 4th monitor setup soon.

Xrandr was showing only 1 monitor connect to DFP3 and the others disconnected for some reason, although I'm sure why that was happening I have managed to fix the issue by simply doing this:

lspci | grep VGA - get the bus ID of the 2nd video card

then edit the /etc/X11/xorg.conf and manually add in the 3rd monitor settings and 2nd device (actually third device according to xorg.conf) with the new bus ID.

rebooted and it works properly...

hope this helps someone else.