Linux - X configuration options

Updated 09/29/2021 09:52 AM

X configuration options


The following driver options are supported by the NVIDIA X driver. They may be specified either in the Screen or Device sections of the X config file.

Option "NvAGP" "integer"

Configure AGP support. Integer argument can be one of:

0 : disable agp

1 : use NVIDIA's internal AGP support, if possible

2 : use AGPGART, if possible

3 : use any agp support (try AGPGART, then NVIDIA's AGP)

Please note that NVIDIA's internal AGP support cannot work if AGPGART is either statically compiled into your kernel or is built as a module, but loaded into your kernel (some distributions load AGPGART into the kernel at boot up). Default: 3 (the default was 1 until after 1.0-1251).

Option "NoLogo" "boolean"

Disable drawing of the NVIDIA logo splash screen at X startup. Default: the logo is drawn.

Option "RenderAccel" "boolean"

Enable or disable hardware acceleration of the RENDER extension. THIS OPTION IS EXPERIMENTAL. ENABLE IT AT YOUR OWN RISK. There is no correctness test suite for the RENDER extension so NVIDIA can not verify that RENDER acceleration works correctly. Default: hardware acceleration of the RENDER extension is disabled.

Option "NoRenderExtension" "boolean"

Disable the RENDER extension. Other than recompiling the X-server, XFree86 does not seem to have another way of disabling this. Fortunately, we can control this from the driver so we export this option. This is useful in depth 8 where RENDER would normally steal most of the default colormap. Default: RENDER is offered when possible.

Option "UBB" "boolean"

Enable or disable Unified Back Buffer on any Quadro based GPUs (Quadro4 NVS excluded); please see Appendix M for a description of UBB. This option has no affect on non-Quadro chipsets. Default: UBB is on for Quadro chipsets.

Option "NoFlip" "boolean"

Disable OpenGL flipping; please see Appendix M for a description. Default: OpenGL will swap by flipping when possible.

Option "DigitalVibrance" "integer"

Enables Digital Vibrance Control. The range of valid values are 0 through 255. This feature is not available on products older than GeForce2. Default: 0.

Option "Dac8Bit" "boolean"

Most Quadro parts by default use a 10 bit color look up table (LUT) by default; setting this option to TRUE forces these graphics chips to use an 8 bit (LUT). Default: a 10 bit LUT is used, when available.

Option "Overlay" "boolean"

Enables RGB workstation overlay visuals. This is only supported on Quadro4 and Quadro FX chips (Quadro4 NVS excluded) in depth 24. This option causes the server to advertise the SERVER_OVERLAY_VISUALS root window property and GLX will report single and double buffered, Z-buffered 16 bit overlay visuals. The transparency key is pixel 0x0000 (hex). There is no gamma correction support in the overlay plane. This feature requires XFree86 version 4.1.0 or newer (or the Xorg X server). NV17/18 based Quadros (ie. 500/550 XGL) have additional restrictions, namely, overlays are not supported in TwinView mode or with virtual desktops larger than 2046x2047 in any dimension (eg. it will not work in 2048x1536 modes). Quadro 7xx/9xx and Quadro FX will offer overlay visuals in these modes (TwinView, or virtual desktops larger than 2046x2047), but the overlay will be emulated with a substantial performance penalty. RGB workstation overlays are not supported when the Composite extension is enabled. Default: off.

Option "CIOverlay" "boolean"

Enables Color Index workstation overlay visuals with identical restrictions to Option "Overlay" above. The server will offer visuals both with and without a transparency key. These are depth 8 PseudoColor visuals. Enabling Color Index overlays on X servers older than XFree86 4.3 will force the RENDER extension to be disabled due to bugs in the RENDER extension in older X servers. Color Index workstation overlays are not supported when the Composite extension is enabled. Default: off.

Option "TransparentIndex" "integer"

When color index overlays are enabled, use this option to choose which pixel is used for the transparent pixel in visuals featuring transparent pixels. This value is clamped between 0 and 255 (Note: some applications such as Alias's Maya require this to be zero in order to work correctly). Default: 0.

Option "OverlayDefaultVisual" "boolean"

When overlays are used, this option sets the default visual to an overlay visual thereby putting the root window in the overlay. This option is not recommended for RGB overlays. Default: off.

Option "SWCursor" "boolean"

Enable or disable software rendering of the X cursor. Default: off.

Option "HWCursor" "boolean"

Enable or disable hardware rendering of the X cursor. Default: on.

Option "CursorShadow" "boolean"

Enable or disable use of a shadow with the hardware accelerated cursor; this is a black translucent replica of your cursor shape at a given offset from the real cursor. This option is only available on GeForce2 or better hardware (ie everything but TNT/TNT2, GeForce 256, GeForce DDR and Quadro). Default: no cursor shadow.

Option "CursorShadowAlpha" "integer"

The alpha value to use for the cursor shadow; only applicable if CursorShadow is enabled. This value must be in the range [0, 255] -- 0 is completely transparent; 255 is completely opaque. Default: 64.

Option "CursorShadowXOffset" "integer"

The offset, in pixels, that the shadow image will be shifted to the right from the real cursor image; only applicable if CursorShadow is enabled. This value must be in the range [0, 32]. Default: 4.

Option "CursorShadowYOffset" "integer"

The offset, in pixels, that the shadow image will be shifted down from the real cursor image; only applicable if CursorShadow is enabled. This value must be in the range [0, 32]. Default: 2.

Option "ConnectedMonitor" "string"

Allows you to override what the NVIDIA kernel module detects is connected to your video card. This may be useful, for example, if you use a KVM (keyboard, video, mouse) switch and you are switched away when X is started. In such a situation, the NVIDIA kernel module cannot detect what display devices are connected, and the NVIDIA X driver assumes you have a single CRT.

Valid values for this option are "CRT" (cathode ray tube), "DFP" (digital flat panel), or "TV" (television); if using TwinView, this option may be a comma-separated list of display devices; e.g.: "CRT, CRT" or "CRT, DFP".

NOTE: anything attached to a 15 pin VGA connector is regarded by the driver as a CRT. "DFP" should only be used to refer to flatpanels connected via a DVI port.

Default: string is NULL.

Option "UseEdidFreqs" "boolean"

This option causes the X server to use the HorizSync and VertRefresh ranges given in a display device's EDID, if any. EDID provided range information will override the HorizSync and VertRefresh ranges specified in the Monitor section. If a display device does not provide an EDID, or the EDID does not specify an hsync or vrefresh range, then the X server will default to the HorizSync and VertRefresh ranges specified in the Monitor section.

Option "IgnoreEDID" "boolean"

Disable probing of EDID (Extended Display Identification Data) from your monitor. Requested modes are compared against values gotten from your monitor EDIDs (if any) during mode validation. Some monitors are known to lie about their own capabilities. Ignoring the values that the monitor gives may help get a certain mode validated.On the other hand, this may be dangerous if you do not know what you are doing. Default: Use EDIDs.

Option "NoDDC" "boolean"

Synonym for "IgnoreEDID"

Option "FlatPanelProperties" "string"

Requests particular properties of any connected flat panels as a comma-separated list of property=value pairs. Currently, the only two available properties are 'Scaling' and 'Dithering'. The possible values for 'Scaling' are: 'default' (the driver will use whatever scaling state is current), 'native' (the driver will use the flat panel's scaler, if it has one), 'scaled' (the driver will use the NVIDIA scaler, if possible), 'centered' (the driver will center the image, if possible), and 'aspect-scaled' (the driver will scale with the NVIDIA scaler, but keep the aspect ratio correct). The possible values for 'Dithering' are: 'default' (the driver will decide when to dither), 'enabled' (the driver will always dither when possible), and 'disabled' (the driver will never dither). If any property is not specified, it's value shall be 'default'. An example properties string might look like:

"Scaling = centered, Dithering = enabled"

Option "UseInt10Module" "boolean"

Enable use of the X Int10 module to soft-boot all secondary cards, rather than POSTing the cards through the NVIDIA kernel module. Default: off (POSTing is done through the NVIDIA kernel module).

NOTE: For details on Twinview, see the article titled "Linux - Configuring Twinview."

Option "TwinView" "boolean"

Enable or disable TwinView. Default: TwinView is disabled.

Option "TwinViewOrientation" "string"

Controls the relationship between the two display devices when using TwinView. Takes one of the following values: "RightOf" "LeftOf" "Above" "Below" "Clone". Default: string is NULL.

Option "SecondMonitorHorizSync" "range(s)"

This option is like the HorizSync entry in the Monitor section, but is for the second monitor when using TwinView. Default: none.

Option "SecondMonitorVertRefresh" "range(s)"

This option is like the VertRefresh entry in the Monitor section, but is for the second monitor when using TwinView. Default: none.

Option "MetaModes" "string"

This option describes the combination of modes to use on each monitor when using TwinView. Default: string is NULL.

Option "NoTwinViewXineramaInfo" "boolean"

When in TwinView, the NVIDIA X driver normally provides a Xinerama extension that X clients (such as window managers) can use to to discover the current TwinView configuration. Some window mangers can get confused by this information, so this option is provided to disable this behavior. Default: TwinView Xinerama information is provided.

Option "TVStandard" "string"

Please see the article titled "Linux - Configuring TV-Out."

Option "TVOutFormat" "string"

Please see the article titled "Linux - Configuring TV-Out."

Option "TVOverScan" "Decimal value in the range 0.0 to 1.0"

Valid values are in the range 0.0 through 1.0. Please see the article titled "Linux - Configuring TV-Out."

Option "Stereo" "integer"

Enable offering of quad-buffered stereo visuals on Quadro. Integer indicates the type of stereo glasses being used:

  1. 1 - DDC glasses. The sync signal is sent to the glasses via the DDC signal to the monitor. These usually involve a passthrough cable between the monitor and video card.

  2. 2 - "Blueline" glasses. These usually involve a passthrough cable between the monitor and video card. The glasses know which eye to display based on the length of a blue line visible at the bottom of the screen. When in this mode, the root window dimensions are one pixel shorter in the Y dimension than requested. This mode does not work with virtual root window sizes larger than the visible root window size (desktop panning).

  3. 3 - Onboard stereo support. This is usually only found on professional cards. The glasses connect via a DIN connector on the back of the video card.

  4. 4 - TwinView clone mode stereo (aka "passive" stereo). On video cards that support TwinView, the left eye is displayed on the first display, and the right eye is displayed on the second display. This is normally used in conjunction with special projectors to produce 2 polarized images which are then viewed with polarized glasses. To use this stereo mode, you must also configure TwinView in clone mode with the same resolution, panning offset, and panning domains on each display.

  5. Stereo is only available on Quadro cards. Stereo options 1, 2, and 3 (aka "active" stereo) may be used with TwinView if all modes within each metamode have identical timing values. Please see the article titled "Linux - Programming modes" for suggestions on making sure the modes within your metamodes are identical. The identical modeline requirement is not necessary for Stereo option 4 ("passive" stereo). Currently, stereo operation may be "quirky" on the original Quadro (NV10) chip and left-right flipping may be erratic. We are trying to resolve this issue for a future release. Default: Stereo is not enabled.

    Stereo options 1, 2, and 3 (aka "active" stereo) are not supported on Digital Flatpanels.

    Option "AllowDFPStereo" "boolean"

    By default, the NVIDIA X driver performs a check which disables active stereo (stereo options 1, 2, and 3) if the X screen is driving a DFP. The "AllowDFPStereo" option bypasses this check.

    Option "NoBandWidthTest" "boolean"

    As part of mode validation, the X driver tests if a given mode fits within the hardware's memory bandwidth constraints. This option disables this test. Default: the memory bandwidth test is performed.

    Option "IgnoreDisplayDevices" "string"

    This option tells the NVIDIA kernel module to completely ignore the indicated classes of display devices when checking what display devices are connected. You may specify a comma-separated list containing any of "CRT", "DFP", and "TV".

    For example:

    Option "IgnoreDisplayDevices" "DFP, TV" will cause the NVIDIA driver to not attempt to detect if any flatpanels or TVs are connected.

    This option is not normally necessary; however, some video BIOSes contain incorrect information about what display devices may be connected, or what i2c port should be used for detection. These errors can cause long delays in starting X. If you are experiencing such delays, you may be able to avoid this by telling the NVIDIA driver to ignore display devices which you know are not connected.

    NOTE: anything attached to a 15 pin VGA connector is regarded by the driver as a CRT. "DFP" should only be used to refer to flatpanels connected via a DVI port.

    Option "MultisampleCompatibility" "boolean"

    Enable or disable the use of separate front and back multisample buffers. This will consume more memory but is necessary for correct output when rendering to both the front and back buffers of a multisample or FSAA drawable. This option is necessary for correct operation of SoftImage XSI. Default: a singlemultisample buffer is shared between the front and back buffers.

    Option "NoPowerConnectorCheck" "boolean"

    The NVIDIA X driver will abort X server initialization if it detects that a GPU that requires an external power connector does not have an external power connector plugged in. This option can be used to bypass this test. Default: the power connector test is performed.

    Option "XvmcUsesTextures" "boolean"

    Forces XvMC to use the 3D engine for XvMCPutSurface requests rather than the video overlay. Default: video overlay is used when available.

    Option "AllowGLXWithComposite" "boolean"

    Enables GLX even when the Composite X extension is loaded. ENABLE AT YOUR OWN RISK. OpenGL applications will not display correctly in many circumstances with this setting enabled. Default: GLX is disabled when Composite is loaded.

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