oracular (3) XPresentQueryCapabilities.3.gz

NAME

       XPresentQueryCapabilities - query capabilities of a CRTC

SYNTAX

       #include <X11/extensions/Xpresent.h>

       uint32_t XPresentQueryCapabilities (Display *display,  XID target);

DESCRIPTION

       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(3)
       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.

SEE ALSO

       Xpresent(3), XPresentNotifyMSC(3), XPresentPixmap(3), XPresentSelectInput(3)

AUTHORS

       Keith Packard, Intel