Visual computing applications that involve multiple displays, or even multiple windows within a display, can require special signal processing and application controls in order to function properly. For example, in order to produce quality video recording of animated graphics, the graphics display must be synchronized with the video camera. As another example, applications presented on multiple displays must be synchronized in order to complete the illusion of a larger, virtual canvas.
This synchronization is enabled through the frame lock and genlock capabilities of the NVIDIA driver. This section describes the setup and use of frame lock and genlock.
GENLOCK: Genlock refers to the process of synchronizing the pixel scanning of one or more displays to an external synchronization source. NVIDIA Genlock requires the external signal to be either TTL or composite, such as used for NTSC, PAL, or HDTV. It should be noted that the NVIDIA Genlock implementation is guaranteed only to be frame-synchronized, and not necessarily pixel-synchronized.
FRAME LOCK: Frame Lock involves the use of hardware to synchronize the frames on each display in a connected system. When graphics and video are displayed across multiple monitors, frame locked systems help maintain image continuity to create a virtual canvas. Frame lock is especially critical for stereo viewing, where the left and right fields must be in sync across all displays.
In short, to enable genlock means to sync to an external signal. To enable frame lock means to sync 2 or more display devices to a signal generated internally by the hardware, and to use both means to sync 2 or more display devices to an external signal.
SWAP SYNC: Swap sync refers to the synchronization of buffer swaps of multiple application windows. By means of swap sync, applications running on multiple systems can synchronize the application buffer swaps between all the systems. In order to work across multiple systems, swap sync requires that the systems are frame locked.
G-SYNC DEVICE: A G-Sync Device refers to devices capable of Frame lock/Genlock. This can be a graphics card (Quadro FX 3000G) or a stand alone device (Quadro FX G-Sync). See "Supported Hardware" below.
Frame lock and genlock are supported for the following hardware:
| Board | |
|---|---|
| Quadro FX 3000G | |
| Quadro FX G-Sync, used in conjunction with a Quadro FX 4400 or Quadro FX 4500 |
Before you begin, you should check that your hardware has been properly installed. If you are using the Quadro FX 3000G, the genlock/frame lock signal processing hardware is located on the dual-slot card itself, and after installing the card, no additional setup is necessary.
If you are using the Quadro FX G-Sync board in conjunction with a graphics card, the following additional setup steps are required. These steps must be performed when the system is off.
On the Quadro FX G-Sync board, locate the fourteen-pin connector labeled "primary". If the associated ribbon cable is not already joined to this connector, do so now.
Install the Quadro FX G-Sync board in any available slot. Note that the slot itself is only used for support, so even a known "bad" slot is acceptable. The slot must be close enough to the graphics card that the ribbon cable can reach.
Connect the other end of the ribbon cable to the fourteen-pin connector on the graphics card.
You may now boot the system and begin the software setup of genlock and/or frame lock. These instructions assume that you have already successfully installed the NVIDIA Accelerated Linux Driver Set. If you have not done so, please see Chapter 2, Installing the NVIDIA Driver.
Frame lock and genlock are configured through the
nvidia-settings utility. Please see the nvidia-settings(1) man page, and the
nvidia-settings online help (click the "Help" button in the lower
right corner of the interface for per-page help information).
From the nvidia-settings frame lock panel, you may control the addition of G-Sync (and display) devices to the frame lock/genlock group, monitor the status of that group, and enable/disable frame lock and genlock.
After the system has booted and X Windows has been started, run nvidia-settings as
% nvidia-settings
You may wish to start this utility before continuing, as we refer to it frequently in the subsequent discussion.
The setup of genlock and frame lock are described separately. We then describe the use of genlock and frame lock together.
After the system has been booted, connect the external signal to the house sync connector (the BNC connector) on either the graphics card or the G-Sync card. There is a status LED next to the connector. A solid red LED indicates that the hardware cannot detect the timing signal. A green LED indicates that the hardware is detecting a timing signal. An occasional red flash is okay. The G-Sync device (graphics card or G-Sync card) will need to be configured correctly for the signal to be detected.
In the frame lock panel of the nvidia-settings interface, add
the X Server that contains the display and G-Sync devices that you
would like to sync to this external source by clicking the "Add
Devices..." button. An X Server is typically specified in the
format system:m, e.g.:
mycomputer.domain.com:0
or
localhost:0
After adding an X Server, rows will appear in the "G-Sync Devices" section on the frame lock panel that displays relevant status information about the G-Sync devices, GPUs attached to those G-Sync devices and the display devices driven by those GPUs. In particular, the G-Sync rows will display the server name and G-Sync device number along with "Receiving" LED, "Rate", "House" LED, "Port0"/"Port1" Images, and "Delay" information. The GPU rows will display the GPU product name information along with the GPU ID for the server. The Display Device rows will show the display device name and device type along with server/client checkboxes, refresh rate, "Timing" LED and "Stereo" LED.
Once the G-Sync and display devices have been added to the frame lock/genlock group, a Server display device will need to be selected. This is done by selecting the "Server" checkbox of the desired display device.
If you are using a G-Sync card, you must also click the "Use House Sync if Present" checkbox. To enable synchronization of this G-Sync device to the external source, click the "Enable Frame Lock" button. The display device(s) may take a moment to stabilize. If it does not stabilize, you may have selected a synchronization signal that the system cannot support. You should disable synchronization by clicking the "Disable Frame Lock" button and check the external sync signal.
Modifications to genlock settings (e.g., "Use House Sync if Present", "Add Devices...") must be done while synchronization is disabled.
Frame Lock is supported across an arbitrary number of Quadro FX 3000 or Quadro FX G-Sync systems, although mixing the two in the same frame lock group is not supported. Additionally, each system to be included in the frame lock group must be configured with identical mode timings. Please see Appendix J, Programming Modes for information on mode timings.
Connect the systems through their RJ45 ports using standard CAT5 patch cables. These ports are located on the frame lock board itself (either the Quadro FX 3000 or the Quadro FX G-Sync board). Do not connect a frame lock port to an ethernet card or hub. Doing so may permanently damage the hardware The connections should be made in a daisy-chain fashion: each card has two RJ45 ports, call them 1 and 2. Connect port 1 of system A to port 2 of system B, connect port 1 of system B to port 2 of system C, etc. Note that you will always have two empty ports in your frame lock group.
The ports self-configure as inputs or outputs once frame lock is enabled. Each port has a yellow and a green LED that reflect this state. A flashing yellow LED indicates an output and a flashing green LED indicates an input. A solid green LED indicates that the port has not yet configured.
In the frame lock panel of the nvidia-settings interface, add the X server that contains the display devices that you would like to include in the frame lock group by clicking the "Add Devices..." button (see the description for adding display devices in the previous section on GENLOCK SETUP. Like the genlock status indicators, the "Port0" and "Port1" columns in the table on the frame lock panel contain indicators whose states mirror the states of the physical LEDs on the RJ45 ports. Thus, you may monitor the status of these ports from the software interface.
Any X Server can be added to the frame lock group, provided that
The system supporting the X Server is configured to support frame lock and is connected via RJ45 cable to the other systems in the frame lock group.
The system driving nvidia-settings can locate and has display privileges on the X server that is to be included for frame lock.
A system can gain display privileges on a remote system by executing
% xhost +
on the remote system. Please see the xhost(1) man page for details. Typically, frame lock is controlled through one of the systems that will be included in the frame lock group. While this is not a requirement, note that nvidia-settings will only display the frame lock panel when running on an X server that supports frame lock.
To enable synchronization on these display devices, click the "Enable Frame Lock" button. The screens may take a moment to stabilize. If they do not stabilize, you may have selected mode timings that one or more of the systems cannot support. In this case you should disable synchronization by clicking the "Disable Frame Lock" button and refer to Appendix J, Programming Modes for information on mode timings.
Modifications to frame lock settings (e.g. "Add/Remove Devices...") must be done while synchronization is disabled.
The use of frame lock and genlock together is a simple extension of the above instructions for using them separately. You should first follow the instructions for Frame Lock Setup, and then to one of the systems that will be included in the frame lock group, attach an external sync source. In order to sync the frame lock group to this single external source, you must select a display device driven by the gpu connected to the G-Sync card (through the primary connector) that is connected to the external source to be the signal server for the group. This is done by selecting the checkbox labeled "Server" of the tree on the frame lock panel in nvidia-settings. If you are using a G-Sync based frame lock group, you must also select the "Use House Sync if Present" checkbox. Enable synchronization by clicking the "Enable Frame Lock" button. As with other frame lock/genlock controls, you must select the signal server while synchronization is disabled.
With the GLX_NV_swap_group extension, OpenGL applications can be implemented to join a group of applications within a system for local swap sync, and bind the group to a barrier for swap sync across a frame lock group. A universal frame counter is also provided to promote synchronization across applications.
The following restrictions must be met for enabling frame lock:
All display devices set as client in a frame lock group must have the same mode timings as the server (master) display device. If a House Sync signal is used (instead of internal timings), all client display devices must be set to have the same refresh rate as the incoming house sync signal.
All X Screens (driving the selected client/server display devices) must have the same stereo setting. Please see Appendix D, X Config Options for instructions on how to set the stereo X option.
The frame lock server (master) display device must be on a GPU on the primary connector to the G-Sync device.
If connecting a single GPU to a G-Sync device, the primary connector must be used.
In configurations with more than one display device per GPU, we recommend enabling frame lock on all display devices on those GPUs.
The following configurations are currently supported:
Basic Frame Lock: Single GPU, Single X Screen, Single Display Device with or without OpenGL applications that make use of Quad-Buffered Stereo and/or the GLX_NV_swap_group extension.
Frame Lock + TwinView: Single GPU, Single X Screen, Multiple Display Devices with or without OpenGL applications that make use of Quad-Buffered Stereo and/or the GLX_NV_swap_group extension.
Frame Lock + Xinerama: 1 or more GPU(s), Multiple X Screens, Multiple Display Devices with or without OpenGL applications that make use of Quad-Buffered Stereo and/or the GLX_NV_swap_group extension.
Frame Lock + TwinView + Xinerama: 1 or more GPU(s), Multiple X Screens, Multiple Display Devices with or without OpenGL applications that make use of Quad-Buffered Stereo and/or the GLX_NV_swap_group extension.
Frame Lock + SLI SFR, AFR, or SLIAA: 2 GPUs, Single X Screen, Single Display Device with either OpenGL applications that make use of Quad-Buffered Stereo or the GLX_NV_swap_group extension. Note that for Frame Lock + SLI Frame Rendering applications that make use of both Quad-Buffered Stereo and the GLX_NV_swap_group extension are not supported.
NOTE: Only one G-sync device per system is currently supported.