Thank you Konstantin and Mark,
I am using the nVidia driver not the one in the repo although I have
tried both.
The monitors all run at 1920x1080 with hdmi input but they use the hdmi,
dport and dvi outputs of the card. Just because of the cables I had on
hand.
I think the next thing to try is to replace the DVI->HDMI cable with a
DPORT->HDMI cable (this card has 4 DPORT, 1 HDMI, 1 DVI).
I would think both of your experience suggest no software issues.
Thanks again!
Joe
On 04/13/2015 12:48 PM, Konstantin Olchanski wrote:
On Wed, Apr 08, 2015 at 09:21:17PM -0700, Joseph Areeda wrote:
So I bought a new GTX960 which purports to support 4 monitors so I
hooked up a third one but SL6 still only sees 2.
In my experience, requirements for multi-monitor support are poorly
documented for most video cards.
For example, the ASUS Z87/Z97 mobo has 3 video outputs connected
to the on-CPU video. It is supposed to support 3 monitors,
but to actually make it work, I had to get down all the way to
data sheet for the on-CPU video controller where they explain
how due to a missing clock (3 clock sources needed, only 2 available),
all 3 monitors have to run at identical resolution and that
only some combinations of DVI and DisplayPort connections
are supported (3 DVI is okey, 2 DVI + 1 DP not okey, or some such
arcane rules).
In practice, it means that all 3 monitors have to be identical,
all connected with DVI-to-{HDMI,DP,miniDP} cables (passive adapters).
Maybe you have mismatched monitors and your particular combination
cannot be done by the hardware (and good luck finding the nvidia
documentation for this - intel seems to do better with public docs).
Again, in practice, if you have nvidia video card, install latest kmod-nvidia
(from elrepo
or otherwise), run "nvidia-settings" and your monitors do not show up,
you are toast.
(Some vendors are upfront with these problems - ASUS AMD socket AM1 mobo
plainly states - 3 video outputs - VGA, DVI, HDMI - but only 2 monitors
can be connected).
K.O.
I still have some debugery to do but I wanted to ask if anyone has
gotten more than 2 monitors to work on one video card?
That will help direct my efforts.
For the record the output of nvidia-smi looks like:
+------------------------------------------------------+
| NVIDIA-SMI 346.59 Driver Version: 346.59 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile
Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util
Compute M. |
|===============================+======================+======================|
| 0 GeForce GTX 960 Off | 0000:01:00.0 N/A
| N/A |
| 0% 46C P8 N/A / N/A | 370MiB / 2047MiB | N/A
Default |
+-------------------------------+----------------------+----------------------+
+-----------------------------------------------------------------------------+
| Processes: GPU Memory |
| GPU PID Type Process name
Usage |
|=============================================================================|
| 0 C+G Not
Supported |
+-----------------------------------------------------------------------------+
thanks,
Joe
