[elrepo] nvidia monitor layout

[John Hodrien]

I'm having a change in behaviour between 7.2 and CentOS 7.2 CR that I'd
appreciate pointers on either where the bug is or how best to fix.

Two monitors, latest nvidia driver (kmod-nvidia-367.57-1.el7.elrepo.x86_64 on
7.2, and the updated kmod-nvidia-367.57-2.el7.elrepo.x86_64 when I've applied
CR, Quadro 600.

xorg simply says to use nvidia, and has no settings relating to twinview.

Section "Device"
    Identifier  "Videocard0"
    Driver      "nvidia"
EndSection

In both cases it detects two connected display devices:

(--) NVIDIA(0):     DFP-0 (boot)
(--) NVIDIA(0):     DFP-1
Validated MetaModes: "DFP-0:nvidia-auto-select,DFP-1:nvidia-auto-select"

DFP-0 is the DVI connector, expected to be the right monitor, and displays the
BIOS POST screen and console display.  DFP-1 is DisplayPort, and displays
nothing until X starts.

The they diverge. 7.2:

(II) NVIDIA(0): Setting mode "DP-0: nvidia-auto-select @1920x1080 +0+0 {ViewPortIn=1920x1080, ViewPortOut=1920x1080+0+0}"
(II) NVIDIA(0): Setting mode "DP-0: nvidia-auto-select @1920x1080 +0+0 {ViewPortIn=1920x1080, ViewPortOut=1920x1080+0+0},
                            DVI-I-1: nvidia-auto-select @1920x1080 +1920+0 {ViewPortIn=1920x1080, ViewPortOut=1920x1080+0+0}"

DP-0 gets allocated left, DVI-I-1 right

7.2 CR:

(II) NVIDIA(0): Setting mode "DP-0: nvidia-auto-select @1920x1080 +1920+0 {ViewPortIn=1920x1080, ViewPortOut=1920x1080+0+0}"
(II) NVIDIA(0): Setting mode "DP-0: nvidia-auto-select @1920x1080 +1920+0 {ViewPortIn=1920x1080, ViewPortOut=1920x1080+0+0},
                            DVI-I-1: nvidia-auto-select @1920x1080 +0+0 {ViewPortIn=1920x1080, ViewPortOut=1920x1080+0+0}"

DP-0 gets allocated right, and DVI-I-1 left.

I've tested this on two machines so far, and seen the same behaviour on both.

MetaModeOrientation says it defaults to RightOf, so presumably I'm expecting an
orientation defaulting to:

DFP-0 RightOf DFP-1

But that's now what I'm getting.  DFP-0 is the boot console, is DVI-I-1, and
is allocated left.

And yet if I set:

Section "Device"
     Identifier     "Videocard0"
     Driver         "nvidia"
     Option         "MetaModeOrientation" "DFP-0 RightOf DFP-1"
EndSection

I get a slightly confused log message about not finding all display devices:

[   627.269] (II) NVIDIA(0): Validated MetaModes:
[   627.269] (II) NVIDIA(0):     "DFP-0:nvidia-auto-select,DFP-1:nvidia-auto-select"
[   627.269] (II) NVIDIA(0): Virtual screen size determined to be 3840 x 1080
[   627.269] (WW) NVIDIA(0): Unable to find all display devices requested in MetaMode
[   627.269] (WW) NVIDIA(0):     Orientation string "DFP-0 RightOf DFP-1".

But then it works just fine, and the layout matches what I was seeing in 7.2.

jh