Only One Head of Nvidia Working

FredJones · 10-20-2014, 05:56 AM

On my ArchLinux 64bit box, recently nvidia stopped working, due to some upgrade. So I switched to nouveau. But now only one output of my Nvidia card works. Here is what I see:

Code:

[fred@arch ~]$ lspci | grep -i  'vga'
01:00.0 VGA compatible controller: NVIDIA Corporation G98 [GeForce 8400 GS Rev. 2] (rev a1)
[fred@arch ~]$ xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
DVI-I-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 510mm x 290mm
   1920x1080     60.00*+
   1680x1050     59.95  
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1024x768      75.08    60.00  
   800x600       75.00    60.32  
   640x480       75.00    60.00  
   720x400       70.08  
DVI-I-2 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 510mm x 290mm
   1920x1080     60.00*+
   1680x1050     59.95  
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1024x768      75.08    60.00  
   800x600       75.00    60.32  
   640x480       75.00    60.00  
   720x400       70.08

but only one screen works. I switched the screens to test them and both screens work fine--it's the card output not working. If I play with xrandr, it recognizes if I put the screens side by side because the xfce4-panel goes across both screens--I can tell because the icons on the right side disappear.

But the second screen (non-primary) never shows anything.

I suppose it could be that the card just broke (or the DVI to VGA adaptor) but it seems too coincidental that it broke precisely when I switched to nouveau. Also, when I unplug the second monitor I see

Code:

$ xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
DVI-I-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 510mm x 290mm
   1920x1080     60.00*+
   1680x1050     59.95  
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1024x768      75.08    60.00  
   800x600       75.00    60.32  
   640x480       75.00    60.00  
   720x400       70.08  
DVI-I-2 disconnected 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0mm

So at least it detects correctly. If I leave in just the DVI to VGA adaptor with no monitor, I still get "DVI-I-2 disconnected" output.
Nothing shows up still on the second monitor however, when I plug it in.

Any suggestions how to further debug this?

ferrari · 10-23-2014, 02:58 PM

I'm not sure about the multi-display capabilities/quirks with using the nouveau driver (vs nvidia). I wonder if this can be overcome with a bit of manual xrandr tweaking....

https://wiki.archlinux.org/index.php...n_using_xrandr

With both displays attached, does the second display become activated with the following?

Code:

xrandr --output DVI-I-2 --on

Try something like

Code:

xrandr --output DVI-I-2 --auto --output DVI-I-2 --auto --right-of DVI-I-1

or

Code:

 xrandr --output DVI-I-2 --mode 1920x1080  --right-of DVI-I-1

FredJones · 10-24-2014, 05:47 AM

I tried things like that. In the end I downgraded from nvidia 343 to 340 and it works fine again--both screens come up. I wonder if the latest nouvea can't handle older cards...

Drakeo · 10-24-2014, 06:13 AM

little hint about nvidia. they fix their big wrapper as need per mesa and xorg upgrades. You should stick with the driver that was out to handle your system. New is not better. Newer is just different for different systems.And newer cards.

ferrari · 10-24-2014, 03:00 PM

Quote:

I wonder if the latest nouvea can't handle older cards...

Quite likely. As with most drivers and associated hardware, it can take time for support to be included

http://nouveau.freedesktop.org/wiki/

and they do want testers (with new hardware like yours)

http://nouveau.freedesktop.org/wiki/TestersWanted/

(With respect to open source drivers, upgrading the kernel may provide a newer graphics driver, which does have the support required/expected. With proprietary graphics drivers, it can be as drakeo pointed out.)