One of the most useful tools for diagnosing problems is the X log file in /var/log. Lines that begin with (II) are information, (WW) are warnings, and (EE) are errors. You should make sure that the correct config file (i.e. the config file you are editing) is being used; look for the line that begins with:

    (==) Using config file:

Also make sure that the NVIDIA driver is being used, rather than the “nv” or “vesa” driver. Search for

    (II) LoadModule: "nvidia"

Lines from the driver should begin with:

    (II) NVIDIA(0)

By default, the NVIDIA X driver prints relatively few messages to stderr and the X log file. If you need to troubleshoot, then it may be helpful to enable more verbose output by using the X command line options -verbose and -logverbose, which can be used to set the verbosity level for the stderr and log file messages, respectively. The NVIDIA X driver will output more messages when the verbosity level is at or above 5 (X defaults to verbosity level 1 for stderr and level 3 for the log file). So, to enable verbose messaging from the NVIDIA X driver to both the log file and stderr, you could start X with the verbosity level set to 5, by doing the following

    % startx -- -verbose 5 -logverbose 5

No, the NVIDIA FreeBSD Graphics Driver is a native driver. It does provide Linux OpenGL libraries in addition to the native, FreeBSD libraries to enable users to run Linux OpenGL applications.

This release is thread-safe on FreeBSD 5.3 or later systems making use of the libpthread or libthr KSE threading libraries. On these systems, the NVIDIA Linux ABI compatibility libraries are fully thread-safe as well.

The Linux compatibility libraries are not able to correctly determine if they are used in a multithreaded application because the %gs segment register is not initialized correctly for Linux compatibility.

The __GL_SINGLE_THREADED environment variable (set to "1") can be used to work around this issue, but at the cost of thread-safeness.

The NVIDIA driver does not support the graphics component of the XFree86-DGA (Direct Graphics Access) extension. Applications can use the XDGASelectInput() function to acquire relative pointer motion, but graphics-related functions such as XDGASetMode() and XDGAOpenFramebuffer() will fail.

The graphics component of XFree86-DGA is not supported because it requires a CPU mapping of framebuffer memory. As graphics cards ship with increasing quantities of video memory, the NVIDIA X driver has had to switch to a more dynamic memory mapping scheme that is incompatible with DGA. Furthermore, DGA does not cooperate with other graphics rendering libraries such as Xlib and OpenGL because it accesses GPU resources directly.

NVIDIA recommends that applications use OpenGL or Xlib, rather than DGA, for graphics rendering. Using rendering libraries other than DGA will yield better performance and improve interoperability with other X applications.

"Xid" messages indicate that a general GPU error occurred, most often due to the driver misprogramming the GPU or to corruption of the commands sent to the GPU. These messages provide diagnostic information that can be used by NVIDIA to aid in debugging reported problems.

EXT_framebuffer_object is supported on GeForce FX, Quadro FX, and newer GPUs.

Clock frequency settings are not saved/restored automatically by default to avoid potential stability and other problems that may be encountered if the chosen frequency settings differ from the defaults qualified by the manufacturer. You can use the command line below in ~/.xinitrc to automatically apply custom clock frequency settings when the X server is started:

    # nvidia-settings -a GPUOverclockingState=1 -a GPU2DClockFreqs=<GPU>,<MEM> -a GPU3DClockFreqs=<GPU>,<MEM>

Here <GPU> and <MEM> are the desired GPU and video memory frequencies (in MHz), respectively.

The XRandR X extension is not presently aware of multiple display devices on a single X screen; it only sees the MetaMode bounding box, which may contain one or more actual modes. This means that if multiple MetaModes have the same bounding box, XRandR will not be able to distinguish between them.

In order to support DynamicTwinView, the NVIDIA X driver must make each MetaMode appear to be unique to XRandR. Presently, the NVIDIA X driver accomplishes this by using the refresh rate as a unique identifier.

You can use `nvidia-settings -q RefreshRate` to query the actual refresh rate on each display device.

This behavior can be disabled by setting the X configuration option "DynamicTwinView" to FALSE.

For details, see Chapter 12, Configuring TwinView.

If your X config file has a Module section that does not list the "extmod" module, some X server extensions may be missing, resulting in error messages of the form:

Xlib: extension "SHAPE" missing on display ":0.0"
Xlib: extension "XFree86-VidModeExtension" missing on display ":0.0"
Xlib: extension "XFree86-DGA" missing on display ":0.0"

You can solve this problem by adding the line below to your X config file's Module section:

    Load "extmod"