... (II) xfree86: Adding drm device (/dev/dri/card2) (II) Platform probe for /sys/devices/pci0000:ae/0000:ae:00.0/0000:af:00.0/0000:b0:10.0/0000:bb:00.0/0000:bc:01.0/0000:bd:00.0/drm/card2 (II) "glx" will be loaded. This was enabled by default and also specified in the config file. (II) LoadModule: "glx" (II) Loading /usr/lib64/xorg/modules/extensions/libglx.so (II) Module glx: vendor="X.Org Foundation" compiled for 1.20.4, module version = 1.0.0 ABI class: X.Org Server Extension, version 10.0
(==) Matched modesetting as autoconfigured driver 0 (==) Matched fbdev as autoconfigured driver 1 (==) Matched vesa as autoconfigured driver 2 (==) Assigned the driver to the xf86ConfigLayout
(II) LoadModule: "modesetting" (II) Loading /usr/lib64/xorg/modules/drivers/modesetting_drv.so (II) Module modesetting: vendor="X.Org Foundation" compiled for 1.20.4, module version = 1.20.4 Module class: X.Org Video Driver ABI class: X.Org Video Driver, version 24.0 (II) LoadModule: "fbdev" (II) Loading /usr/lib64/xorg/modules/drivers/fbdev_drv.so (II) Module fbdev: vendor="X.Org Foundation" compiled for 1.20.1, module version = 0.5.0 Module class: X.Org Video Driver ABI class: X.Org Video Driver, version 24.0 (II) LoadModule: "vesa" (II) Loading /usr/lib64/xorg/modules/drivers/vesa_drv.so (II) Module vesa: vendor="X.Org Foundation" compiled for 1.20.1, module version = 2.4.0 Module class: X.Org Video Driver ABI class: X.Org Video Driver, version 24.0 (II) modesetting: Driver for Modesetting Kernel Drivers: kms (II) FBDEV: driver for framebuffer: fbdev (II) VESA: driver for VESA chipsets: vesa (II) modeset(0): using drv /dev/dri/card2
The “UseDisplayDevice” X configuration option is a list of one or more display devices, which limits the display devices the NVIDIA X driver will consider for an X screen. The display device names used in the option may be either specific (with a numeric suffix; e.g., “DFP-1”) or general (without a numeric suffix; e.g., “DFP”).
When assigning display devices to X screens, the NVIDIA X driver walks through the list of all (not already assigned) display devices detected as connected. When the “UseDisplayDevice” X configuration option is specified, the X driver will only consider connected display devices which are also included in the “UseDisplayDevice” list. This can be thought of as a “mask” against the connected (and not already assigned) display devices.
Note the subtle difference between this option and the “ConnectedMonitor” option: the “ConnectedMonitor” option overrides which display devices are actually detected, while the “UseDisplayDevice” option controls which of the detected display devices will be used on this X screen.
Of the list of display devices considered for this X screen (either all connected display devices, or a subset limited by the “UseDisplayDevice” option), the NVIDIA X driver first looks at CRTs, then at DFPs. For example, if both a CRT and a DFP are connected, by default the X driver would assign the CRT to this X screen. However, by specifying:
Option "UseDisplayDevice" "DFP"
the X screen would use the DFP instead. Or, if CRT-0, DFP-0, and DFP-1 are connected, the X driver would assign CRT-0 and DFP-0 to the X screen. However, by specifying:
Option "UseDisplayDevice" "CRT-0, DFP-1"
the X screen would use CRT-0 and DFP-1 instead.
Additionally, the special value “none” can be specified for the “UseDisplayDevice” option. When this value is given, any programming of the display hardware is disabled. The NVIDIA driver will not perform any mode validation or mode setting for this X screen. This is intended for use in conjunction with CUDA or in remote graphics solutions such as VNC or Hewlett Packard’s Remote Graphics Software (RGS).
“UseDisplayDevice” defaults to “none” on GPUs that have no display capabilities, such as some Tesla GPUs and some mobile GPUs used in Optimus notebook configurations.
Note the following restrictions for setting the “UseDisplayDevice” to “none”:
OpenGL SyncToVBlank will have no effect.
None of Stereo, Overlay, CIOverlay, or SLI are allowed when “UseDisplayDevice” is set to “none”.