Path: utzoo!utgpu!water!watmath!watdragon!jmsellens
From: jmsellens@watdragon.waterloo.edu (John M. Sellens)
Newsgroups: comp.windows.x
Subject: Server screen blanking for dumb displays
Message-ID: <6290@watdragon.waterloo.edu>
Date: 8 Apr 88 03:12:31 GMT
Distribution: comp
Organization: U of Waterloo, Ontario
Lines: 45

Some displays, for example the DEC qvss, can't turn off the video in
hardware.  So, contrary to the Xqvss man page insisting that it
supports all the standard server features, no matter how you set
the "v" flag to Xqvss, your screen won't blank.  The situation was
the same in X10, and I fixed it there, so I thought that I would
offer my fix for X11 R2.

In the screen saver routine in server/dix/window.c, it first tries to
hardware screen save, by calling the device dependent routine.  If that
doesn't work, it tiles your screen, with changing colours if you have
a colour screen, or with a grey pattern if you don't.  This change
causes it to tile your screen all black if you prefer blanking.
So the effect is the same, it's just not as efficient.

As the comment says, I'm not sure about the purity of this little
code addition, but it seems to work.  I'd be glad to receive a
blessed version of the patch.

John Sellens
U of Waterloo
jmsellens@dragon.waterloo.edu

context diff of X11 R2 server/dix/window.c (pretty simple, eh?):

*** window.c.orig	Thu Apr  7 23:04:22 1988
--- window.c	Thu Apr  7 21:38:32 1988
***************
*** 2859,2864 ****
--- 2859,2874 ----
  		}
                  else
                      attributes[0] = None;
+ 
+ 		if (ScreenSaverBlanking != DontPreferBlanking) {
+ 		    /* device dependent blanking failed, but we prefer
+ 		       to save by blanking the screen, so blank the screen
+ 		       by painting it black.  I'm not sure if this is
+ 		       actually the correct way to do it, but it seems
+ 		       to work. - John Sellens - jmsellens@math.waterloo.edu */
+ 		    attributes[0] = screenInfo.screen[i].blackPixel;
+ 		    mask = CWBackPixel;
+ 		}
  
                  pWin = savedScreenInfo[i].pWindow = 
      			/* We SHOULD check for an error value here XXX */