Comment # 53 on bug 1151290 from Stefan Dirsch

Hmm. I'm wondering whether you have NVIDIA's DRM KMS support  enabled. From the
README:

Chapter 35. Direct Rendering Manager Kernel Modesetting (DRM KMS)
______________________________________________________________________________

The NVIDIA GPU driver package provides a kernel module, nvidia-drm.ko, which
registers a DRM driver with the DRM subsystem of the Linux kernel. The
capabilities advertised by this DRM driver depend on the Linux kernel version
and configuration:


   o PRIME: This is needed to support graphics display offload in RandR 1.4.
     Linux kernel version 3.13 or higher is required, with CONFIG_DRM enabled.

   o Atomic Modeset: This is used for display of non-X11 based desktop
     environments, such as Wayland and Mir. Linux kernel version 4.1 or higher
     is required, with CONFIG_DRM and CONFIG_DRM_KMS_HELPER enabled.


NVIDIA's DRM KMS support is still considered experimental. It is disabled by
default, but can be enabled on suitable kernels with the 'modeset' kernel
module parameter. E.g.,

modprobe -r nvidia-drm ; modprobe nvidia-drm modeset=1


Applications can present through NVIDIA's DRM KMS implementation using any of
the following:


   o The DRM KMS "dumb buffer" mechanism to create and map CPU-accessible
     buffers: DRM_IOCTL_MODE_CREATE_DUMB, DRM_IOCTL_MODE_MAP_DUMB, and
     DRM_IOCTL_MODE_DESTROY_DUMB.

   o Using the EGL_EXT_device_drm, EGL_EXT_output_drm, and
     EGL_EXT_stream_consumer_egloutput EGL extensions to associate EGLStream
     producers with specific DRM KMS planes.



35A. KNOWN ISSUES


   o The NVIDIA DRM KMS implementation is currently incompatible with SLI. The
     X server will fail to initialize SLI if DRM KMS is enabled.

   o The NVIDIA DRM KMS implementation does not yet register an overlay plane:
     only primary and cursor planes are currently provided.

   o Buffer allocation and submission to DRM KMS using gbm is not currently
     supported.