Checking in 17.10 PRIME Synchronization can be enabled & works in UbuntuGnome but doesn't in Ubuntu. Main reason is in UbuntuGnome nvidia_drm.modeset can be enabled, in Ubuntu it can't.
ex.'s
UbuntuGnome, gdm3
$ sudo cat /sys/module/nvidia_drm/parameters/modeset
[sudo] password for doug:
Y
$ xrandr --verbose
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 16384 x 16384
eDP-1-1 connected primary 1920x1080+0+0 (0x46) normal (normal left inverted right x axis y axis) 345mm x 194mm
Identifier: 0x42
Timestamp: 21140
Subpixel: unknown
Gamma: 1.0:1.0:1.0
Brightness: 1.0
Clones:
CRTC: 0
CRTCs: 0 1 2
Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000
filter:
_MUTTER_PRESENTATION_OUTPUT: 0
EDID:
00ffffffffffff0030e4d90200000000
00150103802313780a15d59e59509826
0e505400000001010101010101010101
0101010101017e3680b070381f403020
350059c2100000190000000000000000
00000000000000000000000000fe004c
4720446973706c61790a2020000000fe
004c503135365746312d544c4232004b
PRIME Synchronization: 1
supported: 0, 1
Same machine in Ubuntu
sudo cat /sys/module/nvidia_drm/parameters/modeset
[sudo] password for doug:
N
$ xrandr --verbose
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 16384 x 16384
eDP-1-1 connected primary 1920x1080+0+0 (0x46) normal (normal left inverted right x axis y axis) 345mm x 194mm
Identifier: 0x42
Timestamp: 12578
Subpixel: unknown
Gamma: 1.0:1.0:1.0
Brightness: 1.0
Clones:
CRTC: 0
CRTCs: 0 1 2
Transform: 1.000000 0.000000 0.000000 0.000000 1.000000 0.000000 0.000000 0.000000 1.000000
filter:
EDID:
00ffffffffffff0030e4d90200000000
00150103802313780a15d59e59509826
0e505400000001010101010101010101
0101010101017e3680b070381f403020
350059c2100000190000000000000000
00000000000000000000000000fe004c
4720446973706c61790a2020000000fe
004c503135365746312d544c4232004b
PRIME Synchronization: 0
supported: 0, 1
Checking in 17.10 PRIME Synchronization can be enabled & works in UbuntuGnome but doesn't in Ubuntu. Main reason is in UbuntuGnome nvidia_drm.modeset can be enabled, in Ubuntu it can't.
ex.'s nvidia_ drm/parameters/ modeset
0. 000000 1.000000 0.000000
0. 000000 0.000000 1.000000 PRESENTATION_ OUTPUT: 0 f0030e4d9020000 0000 3780a15d59e5950 9826 101010101010101 0101 e3680b070381f40 3020 019000000000000 0000 0000000000000fe 004c c61790a20200000 00fe 746312d544c4232 004b
UbuntuGnome, gdm3
$ sudo cat /sys/module/
[sudo] password for doug:
Y
$ xrandr --verbose
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 16384 x 16384
eDP-1-1 connected primary 1920x1080+0+0 (0x46) normal (normal left inverted right x axis y axis) 345mm x 194mm
Identifier: 0x42
Timestamp: 21140
Subpixel: unknown
Gamma: 1.0:1.0:1.0
Brightness: 1.0
Clones:
CRTC: 0
CRTCs: 0 1 2
Transform: 1.000000 0.000000 0.000000
filter:
_MUTTER_
EDID:
00fffffffffff
0015010380231
0e50540000000
0101010101017
350059c210000
0000000000000
4720446973706
004c503135365
PRIME Synchronization: 1
supported: 0, 1
Same machine in Ubuntu nvidia_ drm/parameters/ modeset
0. 000000 1.000000 0.000000
0. 000000 0.000000 1.000000 f0030e4d9020000 0000 3780a15d59e5950 9826 101010101010101 0101 e3680b070381f40 3020 019000000000000 0000 0000000000000fe 004c c61790a20200000 00fe 746312d544c4232 004b
sudo cat /sys/module/
[sudo] password for doug:
N
$ xrandr --verbose
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 16384 x 16384
eDP-1-1 connected primary 1920x1080+0+0 (0x46) normal (normal left inverted right x axis y axis) 345mm x 194mm
Identifier: 0x42
Timestamp: 12578
Subpixel: unknown
Gamma: 1.0:1.0:1.0
Brightness: 1.0
Clones:
CRTC: 0
CRTCs: 0 1 2
Transform: 1.000000 0.000000 0.000000
filter:
EDID:
00fffffffffff
0015010380231
0e50540000000
0101010101017
350059c210000
0000000000000
4720446973706
004c503135365
PRIME Synchronization: 0
supported: 0, 1
So until shown otherwise am adding lightdm