Copyright © 2013 Keith Packard

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XPresentQueryCapabilities - query capabilities of a CRTC #include <X11/extensions/Xpresent.h>

uint32_t XPresentQueryCapabilities \^(\^Display *display, XID target\^)\^;

XPresentQueryCapabilities returns a bitmask of the supported capabilities for the target CRTC. If target is a CRTC, then it is used as the target CRTC. If target is a WINDOW, then the target CRTC is selected by the X server from among the CRTCs on the screen specified by the window.

PresentCapabilityAsync means that the target device can flip the scanout buffer mid-frame instead of waiting for a vertical blank interval. The precise latency between the flip request and the actual scanout transition is not defined by this specification, but is intended to be no more than a few scanlines.

PresentCapabilityFence means that the target device can take advantage of SyncFences in the Present operations to improve GPU throughput. The driver must operate correctly in the absence of fences, but may have reduced performance. Using fences for drivers not advertising this capability should have no performance impact.

PresentCapabilityUST means that the target device can scanout the image at an arbitrary UST time value, and is not driven by a periodic scanout timer. Applications specifying UST times for XPresentPixmap (__libmansuffix__) can expect that their image will appear to the user within a short amount of time from that specified in the request. The precise accuracy of the scanout time is not defined by the extension, but is expected to be on the order of milliseconds or less.

Xpresent (__libmansuffix__), XPresentNotifyMSC (__libmansuffix__), XPresentPixmap (__libmansuffix__), XPresentSelectInput (__libmansuffix__) Keith Packard, Intel