First let me say that having used NVIDIA for quite some time I was ready for a “fight” in getting this multi-monitor setup with ATI hardware (being that I had no familiarity with it.) Nothing could be further from the truth, AMD/ATI have done a great job in supporting Linux/X11 (I’m using native drivers) and their GUI program works exactly as it looks like it should.
The card I am using is the HD5870 eyefinity (a beast with 6 monitor outputs). I wanted this to get away from using Xinerama for my 4 monitor setup. As it is, I now have 6 monitors working in an array of 3x2 with the desktop effects working just fine. I recommend this for anyone who wants to use more than 2 monitors by the way.
My question is a simple one, and if there is no “fix” that’s fine too as I am happy with this setup as is. Here’s the weird behavior: I can stretch an application across 3 monitors, no problem at all however it limits me to stretching a application vertically to just one monitor. I can’t see any practical reason for this so I am assuming there is some setting somewhere I just need to learn about to turn off this behavior.
Actually, there is one other thing that perhaps someone knows the answer to… how do you get the ATI driver (or perhaps it’s Xorg controlling this) to acknowledge that the displays are capable of 1680x1050 resolution? It can’t read them because it’s an SVGA connection (through a VGA matrix switcher) so it’s just serving up some assumed defaults. The graphics card is certainly capable of more than the 1400x1050 that it’s defaulting to.
I found a cheats way around the vertical limit. I just drag the app. to the bottom of the bottom monitor; then stretch it to the top of the bottom monitor; then drag it to the top of the top monitor and I have an app that covers two stories of monitors. Obviously I’m hoping someone still knows a real solution.
I can’t provide hands on help as I have not configured an run more that two (side by side) monitors, but do expect those who can help will want to know:
When you say you are using “native drivers”, do you mean fglrx (Catalyst) driver and amdcccle as the GUI for setup?
The latest Catalyst version is 11-9.
The output of
lsmod |grep fglrx
will tell for sure.
Have a look in /etc/X11/xorg.conf. You should see 6 monitor sections. Are they all the same? Do all connect via SVGA?
As a hacking suggestion, you might try backing down to one monitor with a connection that will support an edid connection to the monitor. First save the xorg.conf that works (e.g. rename it), then from console at level 3 get a new xorg.conf with
switch to console by alt+ctl F1
login as root
init 3
aticonfig --initial
init 5
Then use amdcccle to set up the resolution you desire and see what the monitor section in xorg.conf looks like.
You could then go back to the 3x2 setup and edit the 6 monitor sections with the results from the higher resolution setup. This might work or give you a hint as to where you want to get.
You might also see some hints in /var/log/Xorg.0.log
Yes, fglrx, I should have said proprietary rather than native I guess.
Thanks, I started looking at xorg.conf last night. with ATI there is so much less to have to do in the xorg.conf file than when I was running NVIDIA and it was a breeze.
Basically, I added a new mode using xrandr (NVIDIA doesn’t support xrandr); added the mode to each output using xrandr; went back to Catalyst to use the new mode; and saved the result.
Then all hell broke loose as I could not get the monitors to be in the right order anymore! What Catalyst was showing and what was happening no longer matched (after trying many restarts of X11 and moving the monitors around in Catalyst). Fortunately from trying to manually edit the xorg.conf file before I had a copy of my manually edited version so I copied that back over the current xorg.conf and it all worked.
Now, there’s one beef I have with Catalyst. I can’t see any way to automatically “snap” monitors perfectly together so after getting it close with the drag and drop it seems you always need to next edit the xorg.conf if you want a perfect alignment of your monitors.
So this solves the screen resolution problem but I still have no idea about the other issue (height limitation when stretching a window).
Also, a weird behavior has started with the new screen resolutions. Every now and then the cube just rotates to the left as if I have hit the right-hand edge. I suspect there is some bug here as it looks like just occasionally something doesn’t believe that the setup is 3 x 1680 wide (5040) and goes "oh, we’re past the right hand side) and just rotates accordingly. But, it doesn’t happen all the time, just randomly it seems. I’ll wait for it to happen a few more times and maybe I’ll see a pattern.
Fixed. I don’t know why but I can now stretch an app. across my monitors vertically. The only thing I can put it to is that I manually edited xorg.conf file monitor positions so they where position relative to each other perfectly (no gaps.)
Okay, the cube seemingly rotating has been solved so all of these are fixed. Some plugin I turned on allows the cube to be rotated by the mouse wheel when the mouse is not over a window and my mouse wheel was moving very slightly.