[argyllcms] Dispwin vs. xscreensaver

  • From: Geoff Kuenning <geoff@xxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 02 Mar 2015 15:40:32 -0800

Hi, all,

I use dispwin to load my monitor calibrations.  For a long time I've
known that xscreensaver clobbers the dispwin settings; after unlocking
my screen I always have to do "dispwin -L".  I finally found time to do
a bit of tracking.

It appears that on modern RandR setups, dispwin uses XRRSetCrtcGamma to
set the gamma curve.  However, xscreensaver uses XF86VidModeGetGammaRamp
to read the current gamma, and the XF86VidModeSetGammaRamp to perform a
fadeout.  Unfortunately, it seems that GetGammaRamp doesn't return the
ramp set by SetCrtcGamma.  So the SetGammaRamp works like "dispwin -c".

My feeling is that this is either an X server bug (on the theory that
the two interfaces should be compatible) or an xscreensaver bug (on the
theory that it should use SetCrtcGamme if it's available.  But I also
think that I'm more likely to find the necessary expertise on this list,
so I'm starting here.

So...my first question is, where should the problem be fixed?
    Geoff Kuenning   geoff@xxxxxxxxxx   http://www.cs.hmc.edu/~geoff/

Paymasters come in only two sizes: one sort shows you where the book
says that you can't have what you've got coming to you; the second
sort digs through the book until he finds a paragraph that lets you
have what you need even if you don't rate it.  Doughty was the second
        -- Robert A. Heinlein, "The Door Into Summer"

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