D27278: Prevent powerdevil from calling DPMS extension calls when DPMS extension isn't present

[Aleksei Nikiforov]

alnikiforov created this revision.
alnikiforov added reviewers: apol, davidedmundson.
Herald added a project: Plasma.
Herald added a subscriber: plasma-devel.
alnikiforov requested review of this revision.

REVISION SUMMARY
  When DPMS extension isn't available, powerdevil unexpectedly exits due to a call to unavailable DPMS function and Qt error handling for such errors.
  
  Following is a full log of powerdevil process when DPMS extension isn't present:
  
    $ /usr/libexec/kf5/org_kde_powerdevil
    QDBusArgument: read from a write-only object
    QDBusArgument: read from a write-only object
    QDBusArgument: read from a write-only object
    powerdevil: No outputs have backlight property
    powerdevil: Xrandr not supported, trying ddc, helper
    powerdevil: [DDCutilBrightness]  0 display(s) were detected
    powerdevil: org.kde5.powerdevil.backlighthelper.brightness failed
    powerdevil: DPMS extension not available
    The X11 connection broke: Unsupported extension used (code 2)
    XIO:  fatal IO error 2 (No such file or directory) on X server ":0" 
          after 408 requests (408 known processed) with 0 events remaining.
  
  This was detected while running KDE in a VM (without x2go). For some reason 'xdpyinfo -queryExtensions' didn't report DPMS extension being present.
  
  Only change in 'PowerDevilDPMSAction::onProfileUnload' was required to fix issue for me, but changes in other functions could be needed as well, thus I implemented it. Two calls to m_helper, 'm_helper->startFade()' and 'm_helper->stopFade()', had corresponding conditions left intact since it looks like it doesn't call DPMS-related functions.

REPOSITORY
  R122 Powerdevil

REVISION DETAIL
  https://phabricator.kde.org/D27278

AFFECTED FILES
  daemon/actions/dpms/powerdevildpmsaction.cpp

To: alnikiforov, apol, davidedmundson
Cc: plasma-devel, Orage, LeGast00n, The-Feren-OS-Dev, cblack, jraleigh, zachus, fbampaloukas, GB_2, ragreen, ZrenBot, ngraham, alexeymin, himcesjf, lesliezhai, ali-mohamed, jensreuterberg, abetts, sebas, apol, ahiemstra, mart
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