D21899: [platforms/x11][5.12] Force QtQuick to Use Software Rendering on PRIME Systems

ekurzinger created this revision.
ekurzinger added a reviewer: KWin.
ekurzinger added a project: KWin.
Herald added a subscriber: kwin.
ekurzinger requested review of this revision.

REVISION SUMMARY
  Bug 406180 was fixed in Plasma 5.16 and later by commit 
  0124b1ef191fcafe0d0f89287be66b36833586e6 <https://phabricator.kde.org/R108:0124b1ef191fcafe0d0f89287be66b36833586e6>, which
  disables vsync for QtQuick windows. However, a bug
  in Qt prevents this fix from taking effect for any release
  prior to this commit
  https://code.qt.io/cgit/qt/qtbase.git/commit/?id=0c1831178540462da31fd7a4b6d2e446bc84498b
  
  As a workaround for users stuck with an older Qt version,
  this change detects whether PRIME synchronization is
  enabled for any output, and if so, forces QtQuick to use
  software rendering.
  
  BUG: 406180

TEST PLAN
  On a hybrid graphics system, using the proprietary NVIDIA driver
  with PRIME synchronization enabled, perform any action
  causing KWin to create a QtQuick window, such as triggering
  the alt + tab application switcher.
  
  The desktop should not freeze, even if the Qt version in
  use does not include the above commit.

REPOSITORY
  R108 KWin

REVISION DETAIL
  https://phabricator.kde.org/D21899

AFFECTED FILES
  atoms.cpp
  atoms.h
  plugins/platforms/x11/standalone/x11_platform.cpp

To: ekurzinger, #kwin
Cc: kwin, #kwin, LeGast00n, jraleigh, fbampaloukas, GB_2, mkulinski, ragreen, jackyalcine, Pitel, iodelay, bwowk, ZrenBot, ngraham, alexeymin, himcesjf, lesliezhai, ali-mohamed, hardening, jensreuterberg, abetts, sebas, apol, mart