Attributes

Some attributes may only be read; some may require a display_mask argument and others may be valid only for specific target types. This information is encoded in the "permission" comment after each attribute define, and can be queried at run time with XNVCTRLQueryValidAttributeValues() and/or XNVCTRLQueryValidTargetAttributeValues()

Key to Integer Attribute "Permissions":

R: The attribute is readable (in general, all attributes will be readable)

W: The attribute is writable (attributes may not be writable for various reasons: they represent static system information, they can only be changed by changing an XF86Config option, etc).

D: The attribute requires the display mask argument. The attributes NV_CTRL_CONNECTED_DISPLAYS and NV_CTRL_ENABLED_DISPLAYS will be a bitmask of what display devices are connected and what display devices are enabled for use in X, respectively. Each bit in the bitmask represents a display device; it is these bits which should be used as the display_mask when dealing with attributes designated with "D" below. For attributes that do not require the display mask, the argument is ignored.

G: The attribute may be queried using an NV_CTRL_TARGET_TYPE_GPU target type via XNVCTRLQueryTargetAttribute().

F: The attribute may be queried using an NV_CTRL_TARGET_TYPE_FRAMELOCK target type via XNVCTRLQueryTargetAttribute().

NOTE: Unless mentioned otherwise, all attributes may be queried using an NV_CTRL_TARGET_TYPE_X_SCREEN target type via XNVCTRLQueryTargetAttribute().

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