Comment 3 for bug 1752739

Chris, the Nvidia-prime deal is expected as prime-select isn't viable with
the switch to libglvnd. Whether a means to switch gpu's is going to be
provided I've no clue..
The loss of prime sync is a double whammy for hybrid device users,
especially in light of no apparent wayland support for such devices on the
Nvidia side.

On Mar 4, 2018 4:05 PM, "Chris McDonough" <email address hidden> wrote:

I can confirm the results of xrandr and dmesg|grep drm above with the
same kernel and nvidia driver versions on my system (a Thinkpad P50 with
an M2000M).

An additional symptom I have is that the nvidia-settings application no
longer supports PRIME at all; the PRIME Settings category in the
application just doesn't appear. Here's the output when I start the
application.

$ nvidia-settings
** Message: 15:46:31.025: PRIME: No offloading required. Abort
** Message: 15:46:31.026: PRIME: is it supported? no

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Title:
  PRIME Synchronization doesn't work with linux-kernel 4.15.

Status in nvidia-graphics-drivers-390 package in Ubuntu:
  New

Bug description:
  I believe this issue is pretty well known, ex. here on optimus machine
  sudo cat /sys/module/nvidia_drm/parameters/modeset
  [sudo] password for doug:
  Y
  $ xrandr --prop | grep PRIME
        PRIME Synchronization: 0 # this is the one needed to be 1
        PRIME Synchronization: 1
        PRIME Synchronization: 1

  Though suppport seems to be there
  $ dmesg |grep drm
  [ 1.863499] [drm] [nvidia-drm] [GPU ID 0x00000100] Loading driver
  [ 1.863501] [drm] Initialized nvidia-drm 0.0.0 20160202 for
0000:01:00.0 on minor 0
  [ 1.873239] [drm] Memory usable by graphics device = 2048M
  [ 1.873244] fb: switching to inteldrmfb from EFI VGA
  [ 1.873323] [drm] Replacing VGA console driver
  [ 1.879334] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
  [ 1.879334] [drm] Driver supports precise vblank timestamp query.
  [ 1.908246] [drm] Initialized i915 1.6.0 20171023 for 0000:00:02.0 on
minor 1
  [ 1.945491] fbcon: inteldrmfb (fb0) is primary device
  [ 1.945568] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device

  bug report in arch
  https://bugs.archlinux.org/task/57305

  If I install the older 384 driver then again with kernel 4.15 no prime
  sync but with the 4.13 kernel it works fine

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