[elrepo] nvidia driver with EL 7.4 (Xorg 1.19) and multiple monitors

[Derek Schrock]

On Sat, Dec 09, 2017 at 06:51:37PM EST, Derek Schrock wrote:
> Anyone using the elrepo nvidia driver with EL 7.4 (RHEL so far tested)
> and newly included Xorg 1.19 with multiple monitors?  Before 7.4 our
> experience with multimonitor (2+) support with the default elrepo
> install of kmod-nvidia and nvidia-x11-drv for a linear layout (1xN) the
> simple xorg.conf (just the device entry) created by the elrepo package
> the monitor layout would remain static based off the cabling and not
> alternate or change.  Is this expected behavior or have we just been
> very lucky with < EL 7.4?
> 
> So far with out testing of RHEL 7.4 and 375.66 384.90 and 384.98 is that
> once you log out of your GUI session the display layout will rotate,
> shift, or change.   Is anyone else able to reproduce this?
> 
> If we create an xorg.conf that sets the layout this seems to fix the
> issue however we distribute a large number of GUI workstations to remote
> locations that might require a different xorg.conf per-location or even
> per-machine.
> 
> An example of what we're seeing with three displays DFP-4/5/6
> At startup: DFP-4, DFP-5, DFP-6 mousing left to right 4, 5, 6
> Logout: DFP-5, DFP-4, DFP-6 mousing left to right 5, 4, 6
> Logout: DFP-6, DFP-4, DFP-5 mousing left to right 6, 4, 5
> ....
> 
> I don't see a pattern to it other than it's just changing.
> 
> Right now I think it's something with Xorg 1.19 however it could be
> something driver plus 1.19 related.   I don't believe it's elrepo
> specific but looking for feedback from users that are using 7.4 or if
> our previous experience is expected behavior.

You can see the solution to this issue here:

https://devtalk.nvidia.com/default/topic/1027427/linux/nvidia-384-98-and-display-orientation-chaning-when-x-restarts-layout-less-xorg-conf/post/5226491/#5226491

It's possible for some older hardware the kernel param
nvidia-drm.modeset=1 needs set.  We're using NVS 510s.