maintainer-feedback requested: [Bug 287456] x11-servers/xorg-server: backport TearFree page flips

Bugzilla Automation <[email protected]> has asked freebsd-x11 (Nobody)
<[email protected]> for maintainer-feedback:
Bug 287456: x11-servers/xorg-server: backport TearFree page flips
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=287456



--- Description ---
OpenBSD has backported TearFree page flips for the modesetting driver from
X.Org master, where this feature has been languishing due to a lack of a new
xserver release.  The attached patch adds it to our x11-servers/xorg-server
port.

I have extracted this from
https://codeberg.org/OpenBSD/xenocara/commit/b454d6cc15eb77cd44fcdcd64f3da55e75
44774d
(Note that the OpenBSD changeset will not apply directly to xserver 21.1.16
since it got accidentally entangled with local OpenBSD changes.)

It eliminates video tearing for instance on my hardware

[   246.944] (II) modeset(0): glamor X acceleration enabled on Mesa Intel(R) HD
Graphics P4600/P4700 (HSW GT2)

when enabled in xorg.conf:

Section "Device"
  Identifier "Intel Graphics"
  Driver "modesetting"
  Option "TearFree" "on"
EndSection